Tag Archives: browsers

New Ways to Track Internet Browsing

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/08/new_ways_to_tra.html

Interesting research on web tracking: “Who Left Open the Cookie Jar? A Comprehensive Evaluation of Third-Party Cookie Policies:

Abstract: Nowadays, cookies are the most prominent mechanism to identify and authenticate users on the Internet. Although protected by the Same Origin Policy, popular browsers include cookies in all requests, even when these are cross-site. Unfortunately, these third-party cookies enable both cross-site attacks and third-party tracking. As a response to these nefarious consequences, various countermeasures have been developed in the form of browser extensions or even protection mechanisms that are built directly into the browser.

In this paper, we evaluate the effectiveness of these defense mechanisms by leveraging a framework that automatically evaluates the enforcement of the policies imposed to third-party requests. By applying our framework, which generates a comprehensive set of test cases covering various web mechanisms, we identify several flaws in the policy implementations of the 7 browsers and 46 browser extensions that were evaluated. We find that even built-in protection mechanisms can be circumvented by multiple novel techniques we discover. Based on these results, we argue that our proposed framework is a much-needed tool to detect bypasses and evaluate solutions to the exposed leaks. Finally, we analyze the origin of the identified bypass techniques, and find that these are due to a variety of implementation, configuration and design flaws.

The researchers discovered many new tracking techniques that work despite all existing anonymous browsing tools. These have not yet been seen in the wild, but that will change soon.

Three news articles. BoingBoing post.

Amazon Sumerian – Now Generally Available

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/amazon-sumerian-now-generally-available/

We announced Amazon Sumerian at AWS re:Invent 2017. As you can see from Tara‘s blog post (Presenting Amazon Sumerian: An Easy Way to Create VR, AR, and 3D Experiences), Sumerian does not require any specialized programming or 3D graphics expertise. You can build VR, AR, and 3D experiences for a wide variety of popular hardware platforms including mobile devices, head-mounted displays, digital signs, and web browsers.

I’m happy to announce that Sumerian is now generally available. You can create realistic virtual environments and scenes without having to acquire or master specialized tools for 3D modeling, animation, lighting, audio editing, or programming. Once built, you can deploy your finished creation across multiple platforms without having to write custom code or deal with specialized deployment systems and processes.

Sumerian gives you a web-based editor that you can use to quickly and easily create realistic, professional-quality scenes. There’s a visual scripting tool that lets you build logic to control how objects and characters (Sumerian Hosts) respond to user actions. Sumerian also lets you create rich, natural interactions powered by AWS services such as Amazon Lex, Polly, AWS Lambda, AWS IoT, and Amazon DynamoDB.

Sumerian was designed to work on multiple platforms. The VR and AR apps that you create in Sumerian will run in browsers that supports WebGL or WebVR and on popular devices such as the Oculus Rift, HTC Vive, and those powered by iOS or Android.

During the preview period, we have been working with a broad spectrum of customers to put Sumerian to the test and to create proof of concept (PoC) projects designed to highlight an equally broad spectrum of use cases, including employee education, training simulations, field service productivity, virtual concierge, design and creative, and brand engagement. Fidelity Labs (the internal R&D unit of Fidelity Investments), was the first to use a Sumerian host to create an engaging VR experience. Cora (the host) lives within a virtual chart room. She can display stock quotes, pull up company charts, and answer questions about a company’s performance. This PoC uses Amazon Polly to implement text to speech and Amazon Lex for conversational chatbot functionality. Read their blog post and watch the video inside to see Cora in action:

Now that Sumerian is generally available, you have the power to create engaging AR, VR, and 3D experiences of your own. To learn more, visit the Amazon Sumerian home page and then spend some quality time with our extensive collection of Sumerian Tutorials.

Jeff;

 

Enhanced Domain Protections for Amazon CloudFront Requests

Post Syndicated from Colm MacCarthaigh original https://aws.amazon.com/blogs/security/enhanced-domain-protections-for-amazon-cloudfront-requests/

Over the coming weeks, we’ll be adding enhanced domain protections to Amazon CloudFront. The short version is this: the new measures are designed to ensure that requests handled by CloudFront are handled on behalf of legitimate domain owners.

Using CloudFront to receive traffic for a domain you aren’t authorized to use is already a violation of our AWS Terms of Service. When we become aware of this type of activity, we deal with it behind the scenes by disabling abusive accounts. Now we’re integrating checks directly into the CloudFront API and Content Distribution service, as well.

Enhanced Protection against Dangling DNS entries
To use CloudFront with your domain, you must configure your domain to point at CloudFront. You may use a traditional CNAME, or an Amazon Route 53 “ALIAS” record.

A problem can arise if you delete your CloudFront distribution, but leave your DNS still pointing at CloudFront, popularly known as a “dangling” DNS entry. Thankfully, this is very rare, as the domain will no longer work, but we occasionally see customers who leave their old domains dormant. This can also happen if you leave this kind of “dangling” DNS entry pointing at other infrastructure you no longer control. For example, if you leave a domain pointing at an IP address that you don’t control, then there is a risk that someone may come along and “claim” traffic destined for your domain.

In an even more rare set of circumstances, an abuser can exploit a subdomain of a domain that you are actively using. For example, if a customer left “images.example.com” dangling and pointing to a deleted CloudFront distribution which is no longer in use, but they still actively use the parent domain “example.com”, then an abuser could come along and register “images.example.com” as an alternative name on their own distribution and claim traffic that they aren’t entitled to. This also means that cookies may be set and intercepted for HTTP traffic potentially including the parent domain. HTTPS traffic remains protected if you’ve removed the certificate associated with the original CloudFront distribution.

Of course, the best fix for this kind of risk is not to leave dangling DNS entries in the first place. Earlier in February, 2018, we added a new warning to our systems. With this warning, if you remove an alternate domain name from a distribution, you are reminded to delete any DNS entries that may still be pointing at CloudFront.

We also have long-standing checks in the CloudFront API that ensure this kind of domain claiming can’t occur when you are using wildcard domains. If you attempt to add *.example.com to your CloudFront distribution, but another account has already registered www.example.com, then the attempt will fail.

With the new enhanced domain protection, CloudFront will now also check your DNS whenever you remove an alternate domain. If we determine that the domain is still pointing at your CloudFront distribution, the API call will fail and no other accounts will be able to claim this traffic in the future.

Enhanced Protection against Domain Fronting
CloudFront will also be soon be implementing enhanced protections against so-called “Domain Fronting”. Domain Fronting is when a non-standard client makes a TLS/SSL connection to a certain name, but then makes a HTTPS request for an unrelated name. For example, the TLS connection may connect to “www.example.com” but then issue a request for “www.example.org”.

In certain circumstances this is normal and expected. For example, browsers can re-use persistent connections for any domain that is listed in the same SSL Certificate, and these are considered related domains. But in other cases, tools including malware can use this technique between completely unrelated domains to evade restrictions and blocks that can be imposed at the TLS/SSL layer.

To be clear, this technique can’t be used to impersonate domains. The clients are non-standard and are working around the usual TLS/SSL checks that ordinary clients impose. But clearly, no customer ever wants to find that someone else is masquerading as their innocent, ordinary domain. Although these cases are also already handled as a breach of our AWS Terms of Service, in the coming weeks we will be checking that the account that owns the certificate we serve for a particular connection always matches the account that owns the request we handle on that connection. As ever, the security of our customers is our top priority, and we will continue to provide enhanced protection against misconfigurations and abuse from unrelated parties.

Interested in additional AWS Security news? Follow the AWS Security Blog on Twitter.

Ransomware Update: Viruses Targeting Business IT Servers

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/ransomware-update-viruses-targeting-business-it-servers/

Ransomware warning message on computer

As ransomware attacks have grown in number in recent months, the tactics and attack vectors also have evolved. While the primary method of attack used to be to target individual computer users within organizations with phishing emails and infected attachments, we’re increasingly seeing attacks that target weaknesses in businesses’ IT infrastructure.

How Ransomware Attacks Typically Work

In our previous posts on ransomware, we described the common vehicles used by hackers to infect organizations with ransomware viruses. Most often, downloaders distribute trojan horses through malicious downloads and spam emails. The emails contain a variety of file attachments, which if opened, will download and run one of the many ransomware variants. Once a user’s computer is infected with a malicious downloader, it will retrieve additional malware, which frequently includes crypto-ransomware. After the files have been encrypted, a ransom payment is demanded of the victim in order to decrypt the files.

What’s Changed With the Latest Ransomware Attacks?

In 2016, a customized ransomware strain called SamSam began attacking the servers in primarily health care institutions. SamSam, unlike more conventional ransomware, is not delivered through downloads or phishing emails. Instead, the attackers behind SamSam use tools to identify unpatched servers running Red Hat’s JBoss enterprise products. Once the attackers have successfully gained entry into one of these servers by exploiting vulnerabilities in JBoss, they use other freely available tools and scripts to collect credentials and gather information on networked computers. Then they deploy their ransomware to encrypt files on these systems before demanding a ransom. Gaining entry to an organization through its IT center rather than its endpoints makes this approach scalable and especially unsettling.

SamSam’s methodology is to scour the Internet searching for accessible and vulnerable JBoss application servers, especially ones used by hospitals. It’s not unlike a burglar rattling doorknobs in a neighborhood to find unlocked homes. When SamSam finds an unlocked home (unpatched server), the software infiltrates the system. It is then free to spread across the company’s network by stealing passwords. As it transverses the network and systems, it encrypts files, preventing access until the victims pay the hackers a ransom, typically between $10,000 and $15,000. The low ransom amount has encouraged some victimized organizations to pay the ransom rather than incur the downtime required to wipe and reinitialize their IT systems.

The success of SamSam is due to its effectiveness rather than its sophistication. SamSam can enter and transverse a network without human intervention. Some organizations are learning too late that securing internet-facing services in their data center from attack is just as important as securing endpoints.

The typical steps in a SamSam ransomware attack are:

1
Attackers gain access to vulnerable server
Attackers exploit vulnerable software or weak/stolen credentials.
2
Attack spreads via remote access tools
Attackers harvest credentials, create SOCKS proxies to tunnel traffic, and abuse RDP to install SamSam on more computers in the network.
3
Ransomware payload deployed
Attackers run batch scripts to execute ransomware on compromised machines.
4
Ransomware demand delivered requiring payment to decrypt files
Demand amounts vary from victim to victim. Relatively low ransom amounts appear to be designed to encourage quick payment decisions.

What all the organizations successfully exploited by SamSam have in common is that they were running unpatched servers that made them vulnerable to SamSam. Some organizations had their endpoints and servers backed up, while others did not. Some of those without backups they could use to recover their systems chose to pay the ransom money.

Timeline of SamSam History and Exploits

Since its appearance in 2016, SamSam has been in the news with many successful incursions into healthcare, business, and government institutions.

March 2016
SamSam appears

SamSam campaign targets vulnerable JBoss servers
Attackers hone in on healthcare organizations specifically, as they’re more likely to have unpatched JBoss machines.

April 2016
SamSam finds new targets

SamSam begins targeting schools and government.
After initial success targeting healthcare, attackers branch out to other sectors.

April 2017
New tactics include RDP

Attackers shift to targeting organizations with exposed RDP connections, and maintain focus on healthcare.
An attack on Erie County Medical Center costs the hospital $10 million over three months of recovery.
Erie County Medical Center attacked by SamSam ransomware virus

January 2018
Municipalities attacked

• Attack on Municipality of Farmington, NM.
• Attack on Hancock Health.
Hancock Regional Hospital notice following SamSam attack
• Attack on Adams Memorial Hospital
• Attack on Allscripts (Electronic Health Records), which includes 180,000 physicians, 2,500 hospitals, and 7.2 million patients’ health records.

February 2018
Attack volume increases

• Attack on Davidson County, NC.
• Attack on Colorado Department of Transportation.
SamSam virus notification

March 2018
SamSam shuts down Atlanta

• Second attack on Colorado Department of Transportation.
• City of Atlanta suffers a devastating attack by SamSam.
The attack has far-reaching impacts — crippling the court system, keeping residents from paying their water bills, limiting vital communications like sewer infrastructure requests, and pushing the Atlanta Police Department to file paper reports.
Atlanta Ransomware outage alert
• SamSam campaign nets $325,000 in 4 weeks.
Infections spike as attackers launch new campaigns. Healthcare and government organizations are once again the primary targets.

How to Defend Against SamSam and Other Ransomware Attacks

The best way to respond to a ransomware attack is to avoid having one in the first place. If you are attacked, making sure your valuable data is backed up and unreachable by ransomware infection will ensure that your downtime and data loss will be minimal or none if you ever suffer an attack.

In our previous post, How to Recover From Ransomware, we listed the ten ways to protect your organization from ransomware.

  1. Use anti-virus and anti-malware software or other security policies to block known payloads from launching.
  2. Make frequent, comprehensive backups of all important files and isolate them from local and open networks. Cybersecurity professionals view data backup and recovery (74% in a recent survey) by far as the most effective solution to respond to a successful ransomware attack.
  3. Keep offline backups of data stored in locations inaccessible from any potentially infected computer, such as disconnected external storage drives or the cloud, which prevents them from being accessed by the ransomware.
  4. Install the latest security updates issued by software vendors of your OS and applications. Remember to patch early and patch often to close known vulnerabilities in operating systems, server software, browsers, and web plugins.
  5. Consider deploying security software to protect endpoints, email servers, and network systems from infection.
  6. Exercise cyber hygiene, such as using caution when opening email attachments and links.
  7. Segment your networks to keep critical computers isolated and to prevent the spread of malware in case of attack. Turn off unneeded network shares.
  8. Turn off admin rights for users who don’t require them. Give users the lowest system permissions they need to do their work.
  9. Restrict write permissions on file servers as much as possible.
  10. Educate yourself, your employees, and your family in best practices to keep malware out of your systems. Update everyone on the latest email phishing scams and human engineering aimed at turning victims into abettors.

Please Tell Us About Your Experiences with Ransomware

Have you endured a ransomware attack or have a strategy to avoid becoming a victim? Please tell us of your experiences in the comments.

The post Ransomware Update: Viruses Targeting Business IT Servers appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Roku Bans Popular Social IPTV Linking Service cCloud TV

Post Syndicated from Andy original https://torrentfreak.com/roku-bans-popular-social-iptv-linking-service-ccloud-tv-180409/

Despite being one of the more popular set-top box platforms, until last year Roku managed to stay completely out of the piracy conversation.

However, due to abuse of its system by third-parties, last June the Superior Court of Justice of the City of Mexico banned the importation and distribution of Roku devices in the country.

The decision followed a complaint filed by cable TV provider Cablevision, which said that some Roku channels and their users were infringing its distribution rights.

Since then, Roku has been fighting to have the ban lifted, previously informing TF that it expressly prohibits copyright infringement of any kind. That led to several more legal processes yet last month and after considerable effort, the ban was upheld, much to Roku’s disappointment.

“It is necessary for Roku to make adjustments to its software, as other online content distribution platforms do, so that violations of copyrighted content do not take place,” Cablevision said.

Then, at the end of March, Roku suddenly banned the USTVnow channel from its platform, citing a third-party copyright complaint.

In a series of emails with TF, the company declined to offer further details but there is plenty of online speculation that the decision was a move towards the “adjustments” demanded by Cablevision. Today yet more fuel is being poured onto that same fire with Roku’s decision to ban the popular cCloud TV service from its platform.

For those unfamiliar with cCloud TV, it’s a video streaming platform that relies on users to contribute media links found on the web, whether they’re movie and TV shows or live sporting events.

“Project cCloud TV is known as the ‘Popcorn Time for Live TV’. The project started with 50 channels and has grown over time and now has over 4000 channels from all around the world,” its founder ‘Bane’ told TF back in 2016.

“The project was inspired by Popcorn Time and its simplicity for streaming torrents. The service works based on media links that can be found anywhere on the web and the cCloud project makes it easier for users to stream.”

Aside from the vast array of content cCloud offers, its versatility is almost unrivaled. In an addition to working via most modern web browsers, it’s also accessible using smartphones, tablets, Plex media server, Kodi, VLC, and (until recently at least) Roku.

But cCloud and USTVnow aren’t the only services suffering bans at Roku.

As highlighted by CordCuttersNews, other channels are also suffering similar fates, such as XTV that was previously replaced with an FBI warning.

cCloud has had problems on Kodi too. Back in September 2017, TVAddons announced that it had been forced to remove the cCloud addon from its site.

“cCloud TV has been removed from our web site due to a complaint made by Bell, Rogers, Videotron and TVA on June 12th, 2017 as part of their lawsuit against our web site,” the site announced.

“Prior to hearing of the lawsuit, we had never received a single complaint relating to the cCloud TV addon for Kodi. cCloud TV for Kodi was developed by podgod, and was basically an interface for the community-based web service that goes by the same name.”

Last week, TVAddons went on to publish an “blacklist” that lists addons that have the potential to deliver content not authorized by rightsholders. Among many others, the list contains cCloud, meaning that potential users will now have to obtain it directly from the Kodi Bae Repository on Github instead.

At the time of publication, Roku had not responded to TorrentFreak’s request for comment.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN reviews, discounts, offers and coupons.

Engineering deep dive: Encoding of SCTs in certificates

Post Syndicated from Let's Encrypt - Free SSL/TLS Certificates original https://letsencrypt.org/2018/04/04/sct-encoding.html

<p>Let&rsquo;s Encrypt recently <a href="https://community.letsencrypt.org/t/signed-certificate-timestamps-embedded-in-certificates/57187">launched SCT embedding in
certificates</a>.
This feature allows browsers to check that a certificate was submitted to a
<a href="https://en.wikipedia.org/wiki/Certificate_Transparency">Certificate Transparency</a>
log. As part of the launch, we did a thorough review
that the encoding of Signed Certificate Timestamps (SCTs) in our certificates
matches the relevant specifications. In this post, I&rsquo;ll dive into the details.
You&rsquo;ll learn more about X.509, ASN.1, DER, and TLS encoding, with references to
the relevant RFCs.</p>

<p>Certificate Transparency offers three ways to deliver SCTs to a browser: In a
TLS extension, in stapled OCSP, or embedded in a certificate. We chose to
implement the embedding method because it would just work for Let&rsquo;s Encrypt
subscribers without additional work. In the SCT embedding method, we submit
a &ldquo;precertificate&rdquo; with a <a href="#poison">poison extension</a> to a set of
CT logs, and get back SCTs. We then issue a real certificate based on the
precertificate, with two changes: The poison extension is removed, and the SCTs
obtained earlier are added in another extension.</p>

<p>Given a certificate, let&rsquo;s first look for the SCT list extension. According to CT (<a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962
section 3.3</a>),
the extension OID for a list of SCTs is <code>1.3.6.1.4.1.11129.2.4.2</code>. An <a href="http://www.hl7.org/Oid/information.cfm">OID (object
ID)</a> is a series of integers, hierarchically
assigned and globally unique. They are used extensively in X.509, for instance
to uniquely identify extensions.</p>

<p>We can <a href="https://acme-v01.api.letsencrypt.org/acme/cert/031f2484307c9bc511b3123cb236a480d451">download an example certificate</a>,
and view it using OpenSSL (if your OpenSSL is old, it may not display the
detailed information):</p>

<pre><code>$ openssl x509 -noout -text -inform der -in Downloads/031f2484307c9bc511b3123cb236a480d451

CT Precertificate SCTs:
Signed Certificate Timestamp:
Version : v1(0)
Log ID : DB:74:AF:EE:CB:29:EC:B1:FE:CA:3E:71:6D:2C:E5:B9:
AA:BB:36:F7:84:71:83:C7:5D:9D:4F:37:B6:1F:BF:64
Timestamp : Mar 29 18:45:07.993 2018 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:44:02:20:7E:1F:CD:1E:9A:2B:D2:A5:0A:0C:81:E7:
13:03:3A:07:62:34:0D:A8:F9:1E:F2:7A:48:B3:81:76:
40:15:9C:D3:02:20:65:9F:E9:F1:D8:80:E2:E8:F6:B3:
25:BE:9F:18:95:6D:17:C6:CA:8A:6F:2B:12:CB:0F:55:
FB:70:F7:59:A4:19
Signed Certificate Timestamp:
Version : v1(0)
Log ID : 29:3C:51:96:54:C8:39:65:BA:AA:50:FC:58:07:D4:B7:
6F:BF:58:7A:29:72:DC:A4:C3:0C:F4:E5:45:47:F4:78
Timestamp : Mar 29 18:45:08.010 2018 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:46:02:21:00:AB:72:F1:E4:D6:22:3E:F8:7F:C6:84:
91:C2:08:D2:9D:4D:57:EB:F4:75:88:BB:75:44:D3:2F:
95:37:E2:CE:C1:02:21:00:8A:FF:C4:0C:C6:C4:E3:B2:
45:78:DA:DE:4F:81:5E:CB:CE:2D:57:A5:79:34:21:19:
A1:E6:5B:C7:E5:E6:9C:E2
</code></pre>

<p>Now let&rsquo;s go a little deeper. How is that extension represented in
the certificate? Certificates are expressed in
<a href="https://en.wikipedia.org/wiki/Abstract_Syntax_Notation_One">ASN.1</a>,
which generally refers to both a language for expressing data structures
and a set of formats for encoding them. The most common format,
<a href="https://en.wikipedia.org/wiki/X.690#DER_encoding">DER</a>,
is a tag-length-value format. That is, to encode an object, first you write
down a tag representing its type (usually one byte), then you write
down a number expressing how long the object is, then you write down
the object contents. This is recursive: An object can contain multiple
objects within it, each of which has its own tag, length, and value.</p>

<p>One of the cool things about DER and other tag-length-value formats is that you
can decode them to some degree without knowing what they mean. For instance, I
can tell you that 0x30 means the data type &ldquo;SEQUENCE&rdquo; (a struct, in ASN.1
terms), and 0x02 means &ldquo;INTEGER&rdquo;, then give you this hex byte sequence to
decode:</p>

<pre><code>30 06 02 01 03 02 01 0A
</code></pre>

<p>You could tell me right away that decodes to:</p>

<pre><code>SEQUENCE
INTEGER 3
INTEGER 10
</code></pre>

<p>Try it yourself with this great <a href="https://lapo.it/asn1js/#300602010302010A">JavaScript ASN.1
decoder</a>. However, you wouldn&rsquo;t know
what those integers represent without the corresponding ASN.1 schema (or
&ldquo;module&rdquo;). For instance, if you knew that this was a piece of DogData, and the
schema was:</p>

<pre><code>DogData ::= SEQUENCE {
legs INTEGER,
cutenessLevel INTEGER
}
</code></pre>

<p>You&rsquo;d know this referred to a three-legged dog with a cuteness level of 10.</p>

<p>We can take some of this knowledge and apply it to our certificates. As a first
step, convert the above certificate to hex with
<code>xxd -ps &lt; Downloads/031f2484307c9bc511b3123cb236a480d451</code>. You can then copy
and paste the result into
<a href="https://lapo.it/asn1js">lapo.it/asn1js</a> (or use <a href="https://lapo.it/asn1js/#3082062F30820517A0030201020212031F2484307C9BC511B3123CB236A480D451300D06092A864886F70D01010B0500304A310B300906035504061302555331163014060355040A130D4C6574277320456E6372797074312330210603550403131A4C6574277320456E637279707420417574686F72697479205833301E170D3138303332393137343530375A170D3138303632373137343530375A302D312B3029060355040313223563396137662E6C652D746573742E686F66666D616E2D616E64726577732E636F6D30820122300D06092A864886F70D01010105000382010F003082010A0282010100BCEAE8F504D9D91FCFC69DB943254A7FED7C6A3C04E2D5C7DDD010CBBC555887274489CA4F432DCE6D7AB83D0D7BDB49C466FBCA93102DC63E0EB1FB2A0C50654FD90B81A6CB357F58E26E50F752BF7BFE9B56190126A47409814F59583BDD337DFB89283BE22E81E6DCE13B4E21FA6009FC8A7F903A17AB05C8BED85A715356837E849E571960A8999701EAE9CE0544EAAB936B790C3C35C375DB18E9AA627D5FA3579A0FB5F8079E4A5C9BE31C2B91A7F3A63AFDFEDB9BD4EA6668902417D286BE4BBE5E43CD9FE1B8954C06F21F5C5594FD3AB7D7A9CBD6ABF19774D652FD35C5718C25A3BA1967846CED70CDBA95831CF1E09FF7B8014E63030CE7A776750203010001A382032A30820326300E0603551D0F0101FF0404030205A0301D0603551D250416301406082B0601050507030106082B06010505070302300C0603551D130101FF04023000301D0603551D0E041604148B3A21ABADF50C4B30DCCD822724D2C4B9BA29E3301F0603551D23041830168014A84A6A63047DDDBAE6D139B7A64565EFF3A8ECA1306F06082B0601050507010104633061302E06082B060105050730018622687474703A2F2F6F6373702E696E742D78332E6C657473656E63727970742E6F7267302F06082B060105050730028623687474703A2F2F636572742E696E742D78332E6C657473656E63727970742E6F72672F302D0603551D110426302482223563396137662E6C652D746573742E686F66666D616E2D616E64726577732E636F6D3081FE0603551D200481F63081F33008060667810C0102013081E6060B2B0601040182DF130101013081D6302606082B06010505070201161A687474703A2F2F6370732E6C657473656E63727970742E6F72673081AB06082B0601050507020230819E0C819B54686973204365727469666963617465206D6179206F6E6C792062652072656C6965642075706F6E2062792052656C79696E67205061727469657320616E64206F6E6C7920696E206163636F7264616E636520776974682074686520436572746966696361746520506F6C69637920666F756E642061742068747470733A2F2F6C657473656E63727970742E6F72672F7265706F7369746F72792F30820104060A2B06010401D6790204020481F50481F200F0007500DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64000001627313EB19000004030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419007700293C519654C83965BAAA50FC5807D4B76FBF587A2972DCA4C30CF4E54547F478000001627313EB2A0000040300483046022100AB72F1E4D6223EF87FC68491C208D29D4D57EBF47588BB7544D32F9537E2CEC10221008AFFC40CC6C4E3B24578DADE4F815ECBCE2D57A579342119A1E65BC7E5E69CE2300D06092A864886F70D01010B0500038201010095F87B663176776502F792DDD232C216943C7803876FCBEB46393A36354958134482E0AFEED39011618327C2F0203351758FEB420B73CE6C797B98F88076F409F3903F343D1F5D9540F41EF47EB39BD61B62873A44F00B7C8B593C6A416458CF4B5318F35235BC88EABBAA34F3E3F81BD3B047E982EE1363885E84F76F2F079F2B6EEB4ECB58EFE74C8DE7D54DE5C89C4FB5BB0694B837BD6F02BAFD5A6C007D1B93D25007BDA9B2BDBF82201FE1B76B628CE34E2D974E8E623EC57A5CB53B435DD4B9993ADF6BA3972F2B29D259594A94E17BBE06F34AAE5CF0F50297548C4DFFC5566136F78A3D3B324EAE931A14EB6BE6DA1D538E48CF077583C67B52E7E8">this handy link</a>). You can also run <code>openssl asn1parse -i -inform der -in Downloads/031f2484307c9bc511b3123cb236a480d451</code> to use OpenSSL&rsquo;s parser, which is less easy to use in some ways, but easier to copy and paste.</p>

<p>In the decoded data, we can find the OID <code>1.3.6.1.4.1.11129.2.4.2</code>, indicating
the SCT list extension. Per <a href="https://tools.ietf.org/html/rfc5280#page-17">RFC 5280, section
4.1</a>, an extension is defined:</p>

<pre><code>Extension ::= SEQUENCE {
extnID OBJECT IDENTIFIER,
critical BOOLEAN DEFAULT FALSE,
extnValue OCTET STRING
— contains the DER encoding of an ASN.1 value
— corresponding to the extension type identified
— by extnID
}
</code></pre>

<p>We&rsquo;ve found the <code>extnID</code>. The &ldquo;critical&rdquo; field is omitted because it has the
default value (false). Next up is the <code>extnValue</code>. This has the type
<code>OCTET STRING</code>, which has the tag &ldquo;0x04&rdquo;. <code>OCTET STRING</code> means &ldquo;here&rsquo;s
a bunch of bytes!&rdquo; In this case, as described by the spec, those bytes
happen to contain more DER. This is a fairly common pattern in X.509
to deal with parameterized data. For instance, this allows defining a
structure for extensions without knowing ahead of time all the structures
that a future extension might want to carry in its value. If you&rsquo;re a C
programmer, think of it as a <code>void*</code> for data structures. If you prefer Go,
think of it as an <code>interface{}</code>.</p>

<p>Here&rsquo;s that <code>extnValue</code>:</p>

<pre><code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
</code></pre>

<p>That&rsquo;s tag &ldquo;0x04&rdquo;, meaning <code>OCTET STRING</code>, followed by &ldquo;0x81 0xF5&rdquo;, meaning
&ldquo;this string is 245 bytes long&rdquo; (the 0x81 prefix is part of <a href="#variable-length">variable length
number encoding</a>).</p>

<p>According to <a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962, section
3.3</a>, &ldquo;obtained SCTs
can be directly embedded in the final certificate, by encoding the
SignedCertificateTimestampList structure as an ASN.1 <code>OCTET STRING</code>
and inserting the resulting data in the TBSCertificate as an X.509v3
certificate extension&rdquo;</p>

<p>So, we have an <code>OCTET STRING</code>, all&rsquo;s good, right? Except if you remove the
tag and length from extnValue to get its value, you&rsquo;re left with:</p>

<pre><code>04 81 F2 00F0007500DB74AFEEC…
</code></pre>

<p>There&rsquo;s that &ldquo;0x04&rdquo; tag again, but with a shorter length. Why
do we nest one <code>OCTET STRING</code> inside another? It&rsquo;s because the
contents of extnValue are required by RFC 5280 to be valid DER, but a
SignedCertificateTimestampList is not encoded using DER (more on that
in a minute). So, by RFC 6962, a SignedCertificateTimestampList is wrapped in an
<code>OCTET STRING</code>, which is wrapped in another <code>OCTET STRING</code> (the extnValue).</p>

<p>Once we decode that second <code>OCTET STRING</code>, we&rsquo;re left with the contents:</p>

<pre><code>00F0007500DB74AFEEC…
</code></pre>

<p>&ldquo;0x00&rdquo; isn&rsquo;t a valid tag in DER. What is this? It&rsquo;s TLS encoding. This is
defined in <a href="https://tools.ietf.org/html/rfc5246#section-4">RFC 5246, section 4</a>
(the TLS 1.2 RFC). TLS encoding, like ASN.1, has both a way to define data
structures and a way to encode those structures. TLS encoding differs
from DER in that there are no tags, and lengths are only encoded when necessary for
variable-length arrays. Within an encoded structure, the type of a field is determined by
its position, rather than by a tag. This means that TLS-encoded structures are
more compact than DER structures, but also that they can&rsquo;t be processed without
knowing the corresponding schema. For instance, here&rsquo;s the top-level schema from
<a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962, section 3.3</a>:</p>

<pre><code> The contents of the ASN.1 OCTET STRING embedded in an OCSP extension
or X509v3 certificate extension are as follows:

opaque SerializedSCT&lt;1..2^16-1&gt;;

struct {
SerializedSCT sct_list &lt;1..2^16-1&gt;;
} SignedCertificateTimestampList;

Here, &quot;SerializedSCT&quot; is an opaque byte string that contains the
serialized TLS structure.
</code></pre>

<p>Right away, we&rsquo;ve found one of those variable-length arrays. The length of such
an array (in bytes) is always represented by a length field just big enough to
hold the max array size. The max size of an <code>sct_list</code> is 65535 bytes, so the
length field is two bytes wide. Sure enough, those first two bytes are &ldquo;0x00
0xF0&rdquo;, or 240 in decimal. In other words, this <code>sct_list</code> will have 240 bytes. We
don&rsquo;t yet know how many SCTs will be in it. That will become clear only by
continuing to parse the encoded data and seeing where each struct ends (spoiler
alert: there are two SCTs!).</p>

<p>Now we know the first SerializedSCT starts with <code>0075…</code>. SerializedSCT
is itself a variable-length field, this time containing <code>opaque</code> bytes (much like <code>OCTET STRING</code>
back in the ASN.1 world). Like SignedCertificateTimestampList, it has a max size
of 65535 bytes, so we pull off the first two bytes and discover that the first
SerializedSCT is 0x0075 (117 decimal) bytes long. Here&rsquo;s the whole thing, in
hex:</p>

<pre><code>00DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64000001627313EB19000004030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
</code></pre>

<p>This can be decoded using the TLS encoding struct defined in <a href="https://tools.ietf.org/html/rfc6962#page-13">RFC 6962, section
3.2</a>:</p>

<pre><code>enum { v1(0), (255) }
Version;

struct {
opaque key_id[32];
} LogID;

opaque CtExtensions&lt;0..2^16-1&gt;;

struct {
Version sct_version;
LogID id;
uint64 timestamp;
CtExtensions extensions;
digitally-signed struct {
Version sct_version;
SignatureType signature_type = certificate_timestamp;
uint64 timestamp;
LogEntryType entry_type;
select(entry_type) {
case x509_entry: ASN.1Cert;
case precert_entry: PreCert;
} signed_entry;
CtExtensions extensions;
};
} SignedCertificateTimestamp;
</code></pre>

<p>Breaking that down:</p>

<pre><code># Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64
# uint64 timestamp (milliseconds since the epoch)
000001627313EB19
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct
04030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
</code></pre>

<p>To understand the &ldquo;digitally-signed struct,&rdquo; we need to turn back to <a href="https://tools.ietf.org/html/rfc5246#section-4.7">RFC 5246,
section 4.7</a>. It says:</p>

<pre><code>A digitally-signed element is encoded as a struct DigitallySigned:

struct {
SignatureAndHashAlgorithm algorithm;
opaque signature&lt;0..2^16-1&gt;;
} DigitallySigned;
</code></pre>

<p>And in <a href="https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1">section
7.4.1.4.1</a>:</p>

<pre><code>enum {
none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
sha512(6), (255)
} HashAlgorithm;

enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
SignatureAlgorithm;

struct {
HashAlgorithm hash;
SignatureAlgorithm signature;
} SignatureAndHashAlgorithm;
</code></pre>

<p>We have &ldquo;0x0403&rdquo;, which corresponds to sha256(4) and ecdsa(3). The next two
bytes, &ldquo;0x0046&rdquo;, tell us the length of the &ldquo;opaque signature&rdquo; field, 70 bytes in
decimal. To decode the signature, we reference <a href="https://tools.ietf.org/html/rfc4492#page-20">RFC 4492 section
5.4</a>, which says:</p>

<pre><code>The digitally-signed element is encoded as an opaque vector &lt;0..2^16-1&gt;, the
contents of which are the DER encoding corresponding to the
following ASN.1 notation.

Ecdsa-Sig-Value ::= SEQUENCE {
r INTEGER,
s INTEGER
}
</code></pre>

<p>Having dived through two layers of TLS encoding, we are now back in ASN.1 land!
We
<a href="https://lapo.it/asn1js/#304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419">decode</a>
the remaining bytes into a SEQUENCE containing two INTEGERS. And we&rsquo;re done! Here&rsquo;s the whole
extension decoded:</p>

<pre><code># Extension SEQUENCE – RFC 5280
30
# length 0x0104 bytes (260 decimal)
820104
# OBJECT IDENTIFIER
06
# length 0x0A bytes (10 decimal)
0A
# value (1.3.6.1.4.1.11129.2.4.2)
2B06010401D679020402
# OCTET STRING
04
# length 0xF5 bytes (245 decimal)
81F5
# OCTET STRING (embedded) – RFC 6962
04
# length 0xF2 bytes (242 decimal)
81F2
# Beginning of TLS encoded SignedCertificateTimestampList – RFC 5246 / 6962
# length 0xF0 bytes
00F0
# opaque SerializedSCT&lt;1..2^16-1&gt;
# length 0x75 bytes
0075
# Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64
# uint64 timestamp (milliseconds since the epoch)
000001627313EB19
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct – RFC 5426
# SignatureAndHashAlgorithm (ecdsa-sha256)
0403
# opaque signature&lt;0..2^16-1&gt;;
# length 0x0046
0046
# DER-encoded Ecdsa-Sig-Value – RFC 4492
30 # SEQUENCE
44 # length 0x44 bytes
02 # r INTEGER
20 # length 0x20 bytes
# value
7E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD3
02 # s INTEGER
20 # length 0x20 bytes
# value
659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
# opaque SerializedSCT&lt;1..2^16-1&gt;
# length 0x77 bytes
0077
# Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
293C519654C83965BAAA50FC5807D4B76FBF587A2972DCA4C30CF4E54547F478
# uint64 timestamp (milliseconds since the epoch)
000001627313EB2A
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct – RFC 5426
# SignatureAndHashAlgorithm (ecdsa-sha256)
0403
# opaque signature&lt;0..2^16-1&gt;;
# length 0x0048
0048
# DER-encoded Ecdsa-Sig-Value – RFC 4492
30 # SEQUENCE
46 # length 0x46 bytes
02 # r INTEGER
21 # length 0x21 bytes
# value
00AB72F1E4D6223EF87FC68491C208D29D4D57EBF47588BB7544D32F9537E2CEC1
02 # s INTEGER
21 # length 0x21 bytes
# value
008AFFC40CC6C4E3B24578DADE4F815ECBCE2D57A579342119A1E65BC7E5E69CE2
</code></pre>

<p>One surprising thing you might notice: In the first SCT, <code>r</code> and <code>s</code> are twenty
bytes long. In the second SCT, they are both twenty-one bytes long, and have a
leading zero. Integers in DER are two&rsquo;s complement, so if the leftmost bit is
set, they are interpreted as negative. Since <code>r</code> and <code>s</code> are positive, if the
leftmost bit would be a 1, an extra byte has to be added so that the leftmost
bit can be 0.</p>

<p>This is a little taste of what goes into encoding a certificate. I hope it was
informative! If you&rsquo;d like to learn more, I recommend &ldquo;<a href="http://luca.ntop.org/Teaching/Appunti/asn1.html">A Layman&rsquo;s Guide to a
Subset of ASN.1, BER, and DER</a>.&rdquo;</p>

<p><a name="poison"></a>Footnote 1: A &ldquo;poison extension&rdquo; is defined by <a href="https://tools.ietf.org/html/rfc6962#section-3.1">RFC 6962
section 3.1</a>:</p>

<pre><code>The Precertificate is constructed from the certificate to be issued by adding a special
critical poison extension (OID `1.3.6.1.4.1.11129.2.4.3`, whose
extnValue OCTET STRING contains ASN.1 NULL data (0x05 0x00))
</code></pre>

<p>In other words, it&rsquo;s an empty extension whose only purpose is to ensure that
certificate processors will not accept precertificates as valid certificates. The
specification ensures this by setting the &ldquo;critical&rdquo; bit on the extension, which
ensures that code that doesn&rsquo;t recognize the extension will reject the whole
certificate. Code that does recognize the extension specifically as poison
will also reject the certificate.</p>

<p><a name="variable-length"></a>Footnote 2: Lengths from 0-127 are represented by
a single byte (short form). To express longer lengths, more bytes are used (long form).
The high bit (0x80) on the first byte is set to distinguish long form from short
form. The remaining bits are used to express how many more bytes to read for the
length. For instance, 0x81F5 means &ldquo;this is long form because the length is
greater than 127, but there&rsquo;s still only one byte of length (0xF5) to decode.&rdquo;</p>

Tracking Cookies and GDPR

Post Syndicated from Bozho original https://techblog.bozho.net/tracking-cookies-gdpr/

GDPR is the new data protection regulation, as you probably already know. I’ve given a detailed practical advice for what it means for developers (and product owners). However, there’s one thing missing there – cookies. The elephant in the room.

Previously I’ve stated that cookies are subject to another piece of legislation – the ePrivacy directive, which is getting updated and its new version will be in force a few years from now. And while that’s technically correct, cookies seem to be affected by GDPR as well. In a way I’ve underestimated that effect.

When you do a Google search on “GDPR cookies”, you’ll pretty quickly realize that a) there’s not too much information and b) there’s not much technical understanding of the issue.

What appears to be the consensus is that GDPR does change the way cookies are handled. More specifically – tracking cookies. Here’s recital 30:

(30) Natural persons may be associated with online identifiers provided by their devices, applications, tools and protocols, such as internet protocol addresses, cookie identifiers or other identifiers such as radio frequency identification tags. This may leave traces which, in particular when combined with unique identifiers and other information received by the servers, may be used to create profiles of the natural persons and identify them.

How tracking cookies work – a 3rd party (usually an ad network) gives you a code snippet that you place on your website, for example to display ads. That code snippet, however, calls “home” (makes a request to the 3rd party domain). If the 3rd party has previously been used on your computer, it has created a cookie. In the example of Facebook, they have the cookie with your Facebook identifier because you’ve logged in to Facebook. So this cookie (with your identifier) is sent with the request. The request also contains all the details from the page. In effect, you are uniquely identified by an identifier (in the case of Facebook and Google – fully identified, rather than some random anonymous identifier as with other ad networks).

Your behaviour on the website is personal data. It gets associated with your identifier, which in turn is associated with your profile. And all of that is personal data. Who is responsible for collecting the website behaviour data, i.e. who is the “controller”? Is it Facebook (or any other 3rd party) that technically does the collection? No, it’s the website owner, as the behaviour data is obtained on their website, and they have put the tracking piece of code there. So they bear responsibility.

What’s the responsibility? So far it boiled down to displaying the useless “we use cookies” warning that nobody cares about. And the current (old) ePrivacy directive and its interpretations says that this is enough – if the users actions can unambiguously mean that they are fine with cookies – i.e. if they continue to use the website after seeing the warning – then you’re fine. This is no longer true from a GDPR perspective – you are collecting user data and you have to have a lawful ground for processing.

For the data collected by tracking cookies you have two options – “consent” and “legitimate interest”. Legitimate interest will be hard to prove – it is not something that a user reasonably expects, it is not necessary for you to provide the service. If your lawyers can get that option to fly, good for them, but I’m not convinced regulators will be happy with that.

The other option is “consent”. You have to ask your users explicitly – that means “with a checkbox” – to let you use tracking cookies. That has two serious implications – from technical and usability point of view.

  • The technical issue is that the data is sent via 3rd party code as soon as the page loads and before the user can give their consent. And that’s already a violation. You can, of course, have the 3rd party code be dynamically inserted only after the user gives consent, but that will require some fiddling with javascript and might not always work depending on the provider. And you’d have to support opt-out at any time (which would in turn disable the 3rd party snippet). It would require actual coding, rather than just copy-pasting a snippet.
  • The usability aspect is the bigger issue – while you could neatly tuck a cookie warning at the bottom, you’d now have to have a serious, “stop the world” popup that asks for consent if you want anyone to click it. You can, of course, just add a checkbox to the existing cookie warning, but don’t expect anyone to click it.

These aspects pose a significant questions: is it worth it to have tracking cookies? Is developing new functionality worth it, is interrupting the user worth it, and is implementing new functionality just so that users never clicks a hidden checkbox worth it? Especially given that Firefox now blocks all tracking cookies and possibly other browsers will follow?

That by itself is an interesting topic – Firefox has basically implemented the most strict form of requirements of the upcoming ePrivacy directive update (that would turn it into an ePrivacy regulation). Other browsers will have to follow, even though Google may not be happy to block their own tracking cookies. I hope other browsers follow Firefox in tracking protection and the issue will be gone automatically.

To me it seems that it will be increasingly not worthy to have tracking cookies on your website. They add regulatory obligations for you and give you very little benefit (yes, you could track engagement from ads, but you can do that in other ways, arguably by less additional code than supporting the cookie consents). And yes, the cookie consent will be “outsourced” to browsers after the ePrivacy regulation is passed, but we can’t be sure at the moment whether there won’t be technical whack-a-mole between browsers and advertisers and whether you wouldn’t still need additional effort to have dynamic consent for tracking cookies. (For example there are reported issues that Firefox used to make Facebook login fail if tracking protection is enabled. Which could be a simple bug, or could become a strategy by big vendors in the future to force browsers into a less strict tracking protection).

Okay, we’ve decided it’s not worth it managing tracking cookies. But do you have a choice as a website owner? Can you stop your ad network from using them? (Remember – you are liable if users’ data is collected by visiting your website). And currently the answer is no – you can’t disable that. You can’t have “just the ads”. This is part of the “deal” – you get money for the ads you place, but you participate in a big “surveillance” network. Users have a way to opt out (e.g. Google AdWords gives them that option). You, as a website owner, don’t.

Facebook has a recommendations page that says “you take care of getting the consent”. But for example the “like button” plugin doesn’t have an option to not send any data to Facebook.

And sometimes you don’t want to serve ads, just track user behaviour and measure conversion. But even if you ask for consent for that and conditionally insert the plugin/snippet, do you actually know what data it sends? And what it’s used for? Because you have to know in order to inform your users. “Do you agree to use tracking cookies that Facebook has inserted in order to collect data about your behaviour on our website” doesn’t sound compelling.

So, what to do? The easiest thing is just not to use any 3rd party ad-related plugins. But that’s obviously not an option, as ad revenue is important, especially in the publishing industry. I don’t have a good answer, apart from “Regulators should pressure ad networks to provide opt-outs and clearly document their data usage”. They have to do that under GDPR, and while website owners are responsible for their users’ data, the ad networks that are in the role of processors in this case (as you delegate the data collection for your visitors to them) also have obligation to assist you in fulfilling your obligations. So ask Facebook – what should I do with your tracking cookies? And when the regulator comes after a privacy-aware customer files a complaint, you could prove that you’ve tried.

The ethical debate whether it’s wrong to collect data about peoples’ behaviour without their informed consent is an easy one. And that’s why I don’t put blame on the regulators – they are putting the ethical consensus in law. It gets more complicated if not allowing tracking means some internet services are no longer profitable and therefore can’t exist. Can we have the cake and eat it too?

The post Tracking Cookies and GDPR appeared first on Bozho's tech blog.

Flight Sim Company Embeds Malware to Steal Pirates’ Passwords

Post Syndicated from Andy original https://torrentfreak.com/flight-sim-company-embeds-malware-to-steal-pirates-passwords-180219/

Anti-piracy systems and DRM come in all shapes and sizes, none of them particularly popular, but one deployed by flight sim company FlightSimLabs is likely to go down in history as one of the most outrageous.

It all started yesterday on Reddit when Flight Sim user ‘crankyrecursion’ reported a little extra something in his download of FlightSimLabs’ A320X module.

“Using file ‘FSLabs_A320X_P3D_v2.0.1.231.exe’ there seems to be a file called ‘test.exe’ included,” crankyrecursion wrote.

“This .exe file is from http://securityxploded.com and is touted as a ‘Chrome Password Dump’ tool, which seems to work – particularly as the installer would typically run with Administrative rights (UAC prompts) on Windows Vista and above. Can anyone shed light on why this tool is included in a supposedly trusted installer?”

The existence of a Chrome password dumping tool is certainly cause for alarm, especially if the software had been obtained from a less-than-official source, such as a torrent or similar site, given the potential for third-party pollution.

However, with the possibility of a nefarious third-party dumping something nasty in a pirate release still lurking on the horizon, things took an unexpected turn. FlightSimLabs chief Lefteris Kalamaras made a statement basically admitting that his company was behind the malware installation.

“We were made aware there is a Reddit thread started tonight regarding our latest installer and how a tool is included in it, that indiscriminately dumps Chrome passwords. That is not correct information – in fact, the Reddit thread was posted by a person who is not our customer and has somehow obtained our installer without purchasing,” Kalamaras wrote.

“[T]here are no tools used to reveal any sensitive information of any customer who has legitimately purchased our products. We all realize that you put a lot of trust in our products and this would be contrary to what we believe.

“There is a specific method used against specific serial numbers that have been identified as pirate copies and have been making the rounds on ThePirateBay, RuTracker and other such malicious sites,” he added.

In a nutshell, FlightSimLabs installed a password dumper onto ALL users’ machines, whether they were pirates or not, but then only activated the password-stealing module when it determined that specific ‘pirate’ serial numbers had been used which matched those on FlightSimLabs’ servers.

“Test.exe is part of the DRM and is only targeted against specific pirate copies of copyrighted software obtained illegally. That program is only extracted temporarily and is never under any circumstances used in legitimate copies of the product,” Kalamaras added.

That didn’t impress Luke Gorman, who published an analysis slamming the flight sim company for knowingly installing password-stealing malware on users machines, even those who purchased the title legitimately.

Password stealer in action (credit: Luke Gorman)

Making matters even worse, the FlightSimLabs chief went on to say that information being obtained from pirates’ machines in this manner is likely to be used in court or other legal processes.

“This method has already successfully provided information that we’re going to use in our ongoing legal battles against such criminals,” Kalamaras revealed.

While the use of the extracted passwords and usernames elsewhere will remain to be seen, it appears that FlightSimLabs has had a change of heart. With immediate effect, the company is pointing customers to a new installer that doesn’t include code for stealing their most sensitive data.

“I want to reiterate and reaffirm that we as a company and as flight simmers would never do anything to knowingly violate the trust that you have placed in us by not only buying our products but supporting them and FlightSimLabs,” Kalamaras said in an update.

“While the majority of our customers understand that the fight against piracy is a difficult and ongoing battle that sometimes requires drastic measures, we realize that a few of you were uncomfortable with this particular method which might be considered to be a bit heavy handed on our part. It is for this reason we have uploaded an updated installer that does not include the DRM check file in question.”

To be continued………

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN discounts, offers and coupons

The Effects of the Spectre and Meltdown Vulnerabilities

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/01/the_effects_of_3.html

On January 3, the world learned about a series of major security vulnerabilities in modern microprocessors. Called Spectre and Meltdown, these vulnerabilities were discovered by several different researchers last summer, disclosed to the microprocessors’ manufacturers, and patched­ — at least to the extent possible.

This news isn’t really any different from the usual endless stream of security vulnerabilities and patches, but it’s also a harbinger of the sorts of security problems we’re going to be seeing in the coming years. These are vulnerabilities in computer hardware, not software. They affect virtually all high-end microprocessors produced in the last 20 years. Patching them requires large-scale coordination across the industry, and in some cases drastically affects the performance of the computers. And sometimes patching isn’t possible; the vulnerability will remain until the computer is discarded.

Spectre and Meltdown aren’t anomalies. They represent a new area to look for vulnerabilities and a new avenue of attack. They’re the future of security­ — and it doesn’t look good for the defenders.

Modern computers do lots of things at the same time. Your computer and your phone simultaneously run several applications — ­or apps. Your browser has several windows open. A cloud computer runs applications for many different computers. All of those applications need to be isolated from each other. For security, one application isn’t supposed to be able to peek at what another one is doing, except in very controlled circumstances. Otherwise, a malicious advertisement on a website you’re visiting could eavesdrop on your banking details, or the cloud service purchased by some foreign intelligence organization could eavesdrop on every other cloud customer, and so on. The companies that write browsers, operating systems, and cloud infrastructure spend a lot of time making sure this isolation works.

Both Spectre and Meltdown break that isolation, deep down at the microprocessor level, by exploiting performance optimizations that have been implemented for the past decade or so. Basically, microprocessors have become so fast that they spend a lot of time waiting for data to move in and out of memory. To increase performance, these processors guess what data they’re going to receive and execute instructions based on that. If the guess turns out to be correct, it’s a performance win. If it’s wrong, the microprocessors throw away what they’ve done without losing any time. This feature is called speculative execution.

Spectre and Meltdown attack speculative execution in different ways. Meltdown is more of a conventional vulnerability; the designers of the speculative-execution process made a mistake, so they just needed to fix it. Spectre is worse; it’s a flaw in the very concept of speculative execution. There’s no way to patch that vulnerability; the chips need to be redesigned in such a way as to eliminate it.

Since the announcement, manufacturers have been rolling out patches to these vulnerabilities to the extent possible. Operating systems have been patched so that attackers can’t make use of the vulnerabilities. Web browsers have been patched. Chips have been patched. From the user’s perspective, these are routine fixes. But several aspects of these vulnerabilities illustrate the sorts of security problems we’re only going to be seeing more of.

First, attacks against hardware, as opposed to software, will become more common. Last fall, vulnerabilities were discovered in Intel’s Management Engine, a remote-administration feature on its microprocessors. Like Spectre and Meltdown, they affected how the chips operate. Looking for vulnerabilities on computer chips is new. Now that researchers know this is a fruitful area to explore, security researchers, foreign intelligence agencies, and criminals will be on the hunt.

Second, because microprocessors are fundamental parts of computers, patching requires coordination between many companies. Even when manufacturers like Intel and AMD can write a patch for a vulnerability, computer makers and application vendors still have to customize and push the patch out to the users. This makes it much harder to keep vulnerabilities secret while patches are being written. Spectre and Meltdown were announced prematurely because details were leaking and rumors were swirling. Situations like this give malicious actors more opportunity to attack systems before they’re guarded.

Third, these vulnerabilities will affect computers’ functionality. In some cases, the patches for Spectre and Meltdown result in significant reductions in speed. The press initially reported 30%, but that only seems true for certain servers running in the cloud. For your personal computer or phone, the performance hit from the patch is minimal. But as more vulnerabilities are discovered in hardware, patches will affect performance in noticeable ways.

And then there are the unpatchable vulnerabilities. For decades, the computer industry has kept things secure by finding vulnerabilities in fielded products and quickly patching them. Now there are cases where that doesn’t work. Sometimes it’s because computers are in cheap products that don’t have a patch mechanism, like many of the DVRs and webcams that are vulnerable to the Mirai (and other) botnets — ­groups of Internet-connected devices sabotaged for coordinated digital attacks. Sometimes it’s because a computer chip’s functionality is so core to a computer’s design that patching it effectively means turning the computer off. This, too, is becoming more common.

Increasingly, everything is a computer: not just your laptop and phone, but your car, your appliances, your medical devices, and global infrastructure. These computers are and always will be vulnerable, but Spectre and Meltdown represent a new class of vulnerability. Unpatchable vulnerabilities in the deepest recesses of the world’s computer hardware is the new normal. It’s going to leave us all much more vulnerable in the future.

This essay previously appeared on TheAtlantic.com.

GDQ schedule dimmer

Post Syndicated from Eevee original https://eev.ee/release/2018/01/23/gdq-schedule-dimmer/

🔗 Source code on GitHub
🔗 Install, maybe

Does this ever happen to you?

[TODO: insert black and white gif of someone struggling to read the GDQ schedule because it’s a single long table and it’s hard to even keep track of what day you’re looking at, let alone find out what’s going on right now]

Well, no more! Thanks to the power of IavaScript, now it’s like the picture above, which I guess gave it away huh.

Not very useful now, since I forgot to even post about it here before AGDQ ended, but presumably useful in SGDQ since they never seem to change this page at all.

Wait! Before you click on the “install” link above. Firefox users will need Greasemonkey. Chrome used to support user scripts natively, and legends say it still does, but there are so many walls around extensions now that I couldn’t figure out how to make it work, so just get Tampermonkey, which is also available for most other browsers.

Backblaze B2 Supports CORS for Cross Origin Resource Sharing

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/enable-cors-for-cross-origin-resource-sharing/

Host files between domains with B2 CORS Rules

Web pages do their magic by loading assets such as images, videos, fonts, text, and other resources from one or more servers on the internet. Most often, data for a website is stored on the same server where the webpages themselves are stored. Sometimes, though, websites will pull in data from servers located elsewhere on the internet.

Allowing websites to include data from other servers can pose possible security risks. To protect users, web browsers enforce security policies that allow scripts in one web page to access data in a second web page only if both web pages have the same origin (i.e. server). This prevents a malicious or faulty script on one page from obtaining access to data on another page that it shouldn’t.

There are many times, however, when one might want to load assets hosted on other servers across the internet. Resources such as fonts, videos, style sheets, images, and iframes are commonly loaded from other origins. It’s great to restrict access to content that might be unauthorized or dangerous, but the web developer needs to be able to specify when it’s okay to load a resource from a different origin.

That’s where CORS comes in.

What is CORS?

To enable web pages to load content that is stored in a different origin, W3C (World Wide Web Consortium), the international community that develops open standards to ensure the long-term growth of the Web, created the Cross-Origin Resource Sharing (CORS) mechanism that allows web pages to access data with a different origin.

The web page might be located on one origin, e.g.

http://origin-a.com

And some data the web page loads might be located on a different origin, e.g.

http://origin-b.com

CORS requires that the resource server explicitly declare that it’s OK to load the asset from a different origin. The browser accomplishes this by making a “preflight” request to ask the server whether it’s OK to make the cross-origin request. By default, servers will say “no” to preflight requests. Rules must be put into place to enable the server to reply to these preflight requests saying it’s OK to serve the asset to a different origin.

B2 Supports CORS for Cross Origin Resource Sharing

B2 is Backblaze’s general purpose cloud storage that can include any type of data that can be stored in the cloud. With pricing that’s ¼ of Amazon’s S3, web developers use B2 as an origin for web data, including text, numbers, scripts, fonts, images, stylesheets, iframes, and videos.

Backblaze supports the standard CORS mechanism that allows B2 customers to share the content of their buckets with web pages hosted in origins other than B2.

In keeping with CORS practices, B2 servers will say “no” to preflight requests to protect the unauthorized sharing of assets to other origins. Adding CORS rules to your bucket tells B2 which preflight requests to approve. CORS is a security feature that is in addition to normal B2 authorization mechanisms. Requests will still need to present normal B2 authorization tokens to download content from non-public buckets.

B2 Cloud Storage Buckets dialog

B2 Cloud Storage Buckets dialog

CORS Rules for BzFileShare

B2 CORS Rules settings dialog

Learn More about B2 and CORS

You can read all about B2’s support of CORS, and how to add rules to your B2 buckets to serve web assets cross-origin, on Backblaze’s website at CORS: Cross-Origin Resource Sharing.

The post Backblaze B2 Supports CORS for Cross Origin Resource Sharing appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Spectre and Meltdown Attacks Against Microprocessors

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/01/spectre_and_mel_1.html

The security of pretty much every computer on the planet has just gotten a lot worse, and the only real solution — which of course is not a solution — is to throw them all away and buy new ones.

On Wednesday, researchers just announced a series of major security vulnerabilities in the microprocessors at the heart of the world’s computers for the past 15-20 years. They’ve been named Spectre and Meltdown, and they have to do with manipulating different ways processors optimize performance by rearranging the order of instructions or performing different instructions in parallel. An attacker who controls one process on a system can use the vulnerabilities to steal secrets elsewhere on the computer. (The research papers are here and here.)

This means that a malicious app on your phone could steal data from your other apps. Or a malicious program on your computer — maybe one running in a browser window from that sketchy site you’re visiting, or as a result of a phishing attack — can steal data elsewhere on your machine. Cloud services, which often share machines amongst several customers, are especially vulnerable. This affects corporate applications running on cloud infrastructure, and end-user cloud applications like Google Drive. Someone can run a process in the cloud and steal data from every other users on the same hardware.

Information about these flaws has been secretly circulating amongst the major IT companies for months as they researched the ramifications and coordinated updates. The details were supposed to be released next week, but the story broke early and everyone is scrambling. By now all the major cloud vendors have patched their systems against the vulnerabilities that can be patched against.

“Throw it away and buy a new one” is ridiculous security advice, but it’s what US-CERT recommends. It is also unworkable. The problem is that there isn’t anything to buy that isn’t vulnerable. Pretty much every major processor made in the past 20 years is vulnerable to some flavor of these vulnerabilities. Patching against Meltdown can degrade performance by almost a third. And there’s no patch for Spectre; the microprocessors have to be redesigned to prevent the attack, and that will take years. (Here’s a running list of who’s patched what.)

This is bad, but expect it more and more. Several trends are converging in a way that makes our current system of patching security vulnerabilities harder to implement.

The first is that these vulnerabilities affect embedded computers in consumer devices. Unlike our computer and phones, these systems are designed and produced at a lower profit margin with less engineering expertise. There aren’t security teams on call to write patches, and there often aren’t mechanisms to push patches onto the devices. We’re already seeing this with home routers, digital video recorders, and webcams. The vulnerability that allowed them to be taken over by the Mirai botnet last August simply can’t be fixed.

The second is that some of the patches require updating the computer’s firmware. This is much harder to walk consumers through, and is more likely to permanently brick the device if something goes wrong. It also requires more coordination. In November, Intel released a firmware update to fix a vulnerability in its Management Engine (ME): another flaw in its microprocessors. But it couldn’t get that update directly to users; it had to work with the individual hardware companies, and some of them just weren’t capable of getting the update to their customers.

We’re already seeing this. Some patches require users to disable the computer’s password, which means organizations can’t automate the patch. Some antivirus software blocks the patch, or — worse — crashes the computer. This results in a three-step process: patch your antivirus software, patch your operating system, and then patch the computer’s firmware.

The final reason is the nature of these vulnerabilities themselves. These aren’t normal software vulnerabilities, where a patch fixes the problem and everyone can move on. These vulnerabilities are in the fundamentals of how the microprocessor operates.

It shouldn’t be surprising that microprocessor designers have been building insecure hardware for 20 years. What’s surprising is that it took 20 years to discover it. In their rush to make computers faster, they weren’t thinking about security. They didn’t have the expertise to find these vulnerabilities. And those who did were too busy finding normal software vulnerabilities to examine microprocessors. Security researchers are starting to look more closely at these systems, so expect to hear about more vulnerabilities along these lines.

Spectre and Meltdown are pretty catastrophic vulnerabilities, but they only affect the confidentiality of data. Now that they — and the research into the Intel ME vulnerability — have shown researchers where to look, more is coming — and what they’ll find will be worse than either Spectre or Meltdown. There will be vulnerabilities that will allow attackers to manipulate or delete data across processes, potentially fatal in the computers controlling our cars or implanted medical devices. These will be similarly impossible to fix, and the only strategy will be to throw our devices away and buy new ones.

This isn’t to say you should immediately turn your computers and phones off and not use them for a few years. For the average user, this is just another attack method amongst many. All the major vendors are working on patches and workarounds for the attacks they can mitigate. All the normal security advice still applies: watch for phishing attacks, don’t click on strange e-mail attachments, don’t visit sketchy websites that might run malware on your browser, patch your systems regularly, and generally be careful on the Internet.

You probably won’t notice that performance hit once Meltdown is patched, except maybe in backup programs and networking applications. Embedded systems that do only one task, like your programmable thermostat or the computer in your refrigerator, are unaffected. Small microprocessors that don’t do all of the vulnerable fancy performance tricks are unaffected. Browsers will figure out how to mitigate this in software. Overall, the security of the average Internet-of-Things device is so bad that this attack is in the noise compared to the previously known risks.

It’s a much bigger problem for cloud vendors; the performance hit will be expensive, but I expect that they’ll figure out some clever way of detecting and blocking the attacks. All in all, as bad as Spectre and Meltdown are, I think we got lucky.

But more are coming, and they’ll be worse. 2018 will be the year of microprocessor vulnerabilities, and it’s going to be a wild ride.

Note: A shorter version of this essay previously appeared on CNN.com. My previous blog post on this topic contains additional links.

Spectre and Meltdown Attacks

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/01/spectre_and_mel.html

After a week or so of rumors, everyone is now reporting about the Spectre and Meltdown attacks against pretty much every modern processor out there.

These are side-channel attacks where one process can spy on other processes. They affect computers where an untrusted browser window can execute code, phones that have multiple apps running at the same time, and cloud computing networks that run lots of different processes at once. Fixing them either requires a patch that results in a major performance hit, or is impossible and requires a re-architecture of conditional execution in future CPU chips.

I’ll be writing something for publication over the next few days. This post is basically just a link repository.

EDITED TO ADD: Good technical explanation. And a Slashdot thread.

EDITED TO ADD (1/5): Another good technical description. And how the exploits work through browsers. A rundown of what vendors are doing. Nicholas Weaver on its effects on individual computers.

EDITED TO ADD (1/7): xkcd.

EDITED TO ADD (1/10): Another good technical description.

CrimeStoppers Campaign Targets Pirate Set-Top Boxes & Their Users

Post Syndicated from Andy original https://torrentfreak.com/crimestoppers-campaign-targets-pirate-set-top-boxes-their-users-171209/

While many people might believe CrimeStoppers to be an official extension of the police in the UK, the truth is a little more subtle.

CrimeStoppers is a charity that operates a service through which members of the public can report crime anonymously, either using a dedicated phone line or via a website. Callers are not required to give their name, meaning that for those concerned about reprisals or becoming involved in a case for other sensitive reasons, it’s the perfect buffer between them and the authorities.

The people at CrimeStoppers deal with all kinds of crime but perhaps a little surprisingly, they’ve just got involved in the set-top box controversy in the UK.

“Advances in technology have allowed us to enjoy on-screen entertainment in more ways than ever before, with ever increasing amounts of exciting and original content,” the CrimeStoppers campaign begins.

“However, some people are avoiding paying for this content by using modified streaming hardware devices, like a set-top box or stick, in conjunction with software such as illegal apps or add-ons, or illegal mobile apps which allow them to watch new movie releases, TV that hasn’t yet aired, and subscription sports channels for free.”

The campaign has been launched in partnership with the Intellectual Property Office and unnamed “industry partners”. Who these companies are isn’t revealed but given the standard messages being portrayed by the likes of ACE, Premier League and Federation Against Copyright Theft lately, it wouldn’t be a surprise if some or all of them were involved.

Those messages are revealed in a series of four video ads, each taking a different approach towards discouraging the public from using devices loaded with pirate software.

The first video clearly targets the consumer, dispelling the myth that watching pirate video isn’t against the law. It is, that’s not in any doubt, but from the constant tone of the video, one could be forgiven that it’s an extremely serious crime rather than something which is likely to be a civil matter, if anything at all.

It also warns people who are configuring and selling pirate devices that they are breaking the law. Again, this is absolutely true but this activity is clearly several magnitudes more serious than simply viewing. The video blurs the boundaries for what appears to be dramatic effect, however.

Selling and watching is illegal

The second video is all about demonizing the people and groups who may offer set-top boxes to the public.

Instead of portraying the hundreds of “cottage industry” suppliers behind many set-top box sales in the UK, the CrimeStoppers video paints a picture of dark organized crime being the main driver. By buying from these people, the charity warns, criminals are being welcomed in.

“It is illegal. You could also be helping to fund organized crime and bringing it into your community,” the video warns.

Are you funding organized crime?

The third video takes another approach, warning that set-top boxes have few if any parental controls. This could lead to children being exposed to inappropriate content, the charity warns.

“What are your children watching. Does it worry you?” the video asks.

Of course, the same can be said about the Internet, period. Web browsers don’t filter what content children have access to unless parents take pro-active steps to configure special services or software for the purpose.

There’s always the option to supervise children, of course, but Netflix is probably a safer option for those with a preference to stand off. It’s also considerably more expensive, a fact that won’t have escaped users of these devices.

Got kids? Take care….

Finally, video four picks up a theme that’s becoming increasingly common in anti-piracy campaigns – malware and identity theft.

“Why risk having your identity stolen or your bank account or home network hacked. If you access entertainment or sports using dodgy streaming devices or apps, or illegal addons for Kodi, you are increasing the risks,” the ad warns.

Danger….Danger….

Perhaps of most interest is that this entire campaign, which almost certainly has Big Media behind the scenes in advisory and financial capacities, barely mentions the entertainment industries at all.

Indeed, the success of the whole campaign hinges on people worrying about the supposed ill effects of illicit streaming on them personally and then feeling persuaded to inform on suppliers and others involved in the chain.

“Know of someone supplying or promoting these dodgy devices or software? It is illegal. Call us now and help stop crime in your community,” the videos warn.

That CrimeStoppers has taken on this campaign at all is a bit of a head-scratcher, given the bigger crime picture. Struggling with severe budget cuts, police in the UK are already de-prioritizing a number of crimes, leading to something called “screening out”, a process through which victims are given a crime number but no investigation is carried out.

This means that in 2016, 45% of all reported crimes in Greater Manchester weren’t investigated and a staggering 57% of all recorded domestic burglaries weren’t followed up by the police. But it gets worse.

“More than 62pc of criminal damage and arson offenses were not investigated, along with one in three reported shoplifting incidents,” MEN reports.

Given this backdrop, how will police suddenly find the resources to follow up lots of leads from the public and then subsequently prosecute people who sell pirate boxes? Even if they do, will that be at the expense of yet more “screening out” of other public-focused offenses?

No one is saying that selling pirate devices isn’t a crime or at least worthy of being followed up, but is this niche likely to be important to the public when they’re being told that nothing will be done when their homes are emptied by intruders? “NO” says a comment on one of the CrimeStoppers videos on YouTube.

“This crime affects multi-million dollar corporations, I’d rather see tax payers money invested on videos raising awareness of crimes committed against the people rather than the 0.001%,” it concludes.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN discounts, offers and coupons

Looking Forward to 2018

Post Syndicated from Let's Encrypt - Free SSL/TLS Certificates original https://letsencrypt.org//2017/12/07/looking-forward-to-2018.html

Let’s Encrypt had a great year in 2017. We more than doubled the number of active (unexpired) certificates we service to 46 million, we just about tripled the number of unique domains we service to 61 million, and we did it all while maintaining a stellar security and compliance track record. Most importantly though, the Web went from 46% encrypted page loads to 67% according to statistics from Mozilla – a gain of 21% in a single year – incredible. We’re proud to have contributed to that, and we’d like to thank all of the other people and organizations who also worked hard to create a more secure and privacy-respecting Web.

While we’re proud of what we accomplished in 2017, we are spending most of the final quarter of the year looking forward rather than back. As we wrap up our own planning process for 2018, I’d like to share some of our plans with you, including both the things we’re excited about and the challenges we’ll face. We’ll cover service growth, new features, infrastructure, and finances.

Service Growth

We are planning to double the number of active certificates and unique domains we service in 2018, to 90 million and 120 million, respectively. This anticipated growth is due to continuing high expectations for HTTPS growth in general in 2018.

Let’s Encrypt helps to drive HTTPS adoption by offering a free, easy to use, and globally available option for obtaining the certificates required to enable HTTPS. HTTPS adoption on the Web took off at an unprecedented rate from the day Let’s Encrypt launched to the public.

One of the reasons Let’s Encrypt is so easy to use is that our community has done great work making client software that works well for a wide variety of platforms. We’d like to thank everyone involved in the development of over 60 client software options for Let’s Encrypt. We’re particularly excited that support for the ACME protocol and Let’s Encrypt is being added to the Apache httpd server.

Other organizations and communities are also doing great work to promote HTTPS adoption, and thus stimulate demand for our services. For example, browsers are starting to make their users more aware of the risks associated with unencrypted HTTP (e.g. Firefox, Chrome). Many hosting providers and CDNs are making it easier than ever for all of their customers to use HTTPS. Government agencies are waking up to the need for stronger security to protect constituents. The media community is working to Secure the News.

New Features

We’ve got some exciting features planned for 2018.

First, we’re planning to introduce an ACME v2 protocol API endpoint and support for wildcard certificates along with it. Wildcard certificates will be free and available globally just like our other certificates. We are planning to have a public test API endpoint up by January 4, and we’ve set a date for the full launch: Tuesday, February 27.

Later in 2018 we plan to introduce ECDSA root and intermediate certificates. ECDSA is generally considered to be the future of digital signature algorithms on the Web due to the fact that it is more efficient than RSA. Let’s Encrypt will currently sign ECDSA keys from subscribers, but we sign with the RSA key from one of our intermediate certificates. Once we have an ECDSA root and intermediates, our subscribers will be able to deploy certificate chains which are entirely ECDSA.

Infrastructure

Our CA infrastructure is capable of issuing millions of certificates per day with multiple redundancy for stability and a wide variety of security safeguards, both physical and logical. Our infrastructure also generates and signs nearly 20 million OCSP responses daily, and serves those responses nearly 2 billion times per day. We expect issuance and OCSP numbers to double in 2018.

Our physical CA infrastructure currently occupies approximately 70 units of rack space, split between two datacenters, consisting primarily of compute servers, storage, HSMs, switches, and firewalls.

When we issue more certificates it puts the most stress on storage for our databases. We regularly invest in more and faster storage for our database servers, and that will continue in 2018.

We’ll need to add a few additional compute servers in 2018, and we’ll also start aging out hardware in 2018 for the first time since we launched. We’ll age out about ten 2u compute servers and replace them with new 1u servers, which will save space and be more energy efficient while providing better reliability and performance.

We’ll also add another infrastructure operations staff member, bringing that team to a total of six people. This is necessary in order to make sure we can keep up with demand while maintaining a high standard for security and compliance. Infrastructure operations staff are systems administrators responsible for building and maintaining all physical and logical CA infrastructure. The team also manages a 24/7/365 on-call schedule and they are primary participants in both security and compliance audits.

Finances

We pride ourselves on being an efficient organization. In 2018 Let’s Encrypt will secure a large portion of the Web with a budget of only $3.0M. For an overall increase in our budget of only 13%, we will be able to issue and service twice as many certificates as we did in 2017. We believe this represents an incredible value and that contributing to Let’s Encrypt is one of the most effective ways to help create a more secure and privacy-respecting Web.

Our 2018 fundraising efforts are off to a strong start with Platinum sponsorships from Mozilla, Akamai, OVH, Cisco, Google Chrome and the Electronic Frontier Foundation. The Ford Foundation has renewed their grant to Let’s Encrypt as well. We are seeking additional sponsorship and grant assistance to meet our full needs for 2018.

We had originally budgeted $2.91M for 2017 but we’ll likely come in under budget for the year at around $2.65M. The difference between our 2017 expenses of $2.65M and the 2018 budget of $3.0M consists primarily of the additional infrastructure operations costs previously mentioned.

Support Let’s Encrypt

We depend on contributions from our community of users and supporters in order to provide our services. If your company or organization would like to sponsor Let’s Encrypt please email us at [email protected]. We ask that you make an individual contribution if it is within your means.

We’re grateful for the industry and community support that we receive, and we look forward to continuing to create a more secure and privacy-respecting Web!

About the Amazon Trust Services Migration

Post Syndicated from Brent Meyer original https://aws.amazon.com/blogs/ses/669-2/

Amazon Web Services is moving the certificates for our services—including Amazon SES—to use our own certificate authority, Amazon Trust Services. We have carefully planned this change to minimize the impact it will have on your workflow. Most customers will not have to take any action during this migration.

About the Certificates

The Amazon Trust Services Certificate Authority (CA) uses the Starfield Services CA, which has been valid since 2005. The Amazon Trust Services certificates are available in most major operating systems released in the past 10 years, and are also trusted by all modern web browsers.

If you send email through the Amazon SES SMTP interface using a mail server that you operate, we recommend that you confirm that the appropriate certificates are installed. You can test whether your server trusts the Amazon Trust Services CAs by visiting the following URLs (for example, by using cURL):

If you see a message stating that the certificate issuer is not recognized, then you should install the appropriate root certificate. You can download individual certificates from https://www.amazontrust.com/repository. The process of adding a trusted certificate to your server varies depending on the operating system you use. For more information, see “Adding New Certificates,” below.

AWS SDKs and CLI

Recent versions of the AWS SDKs and the AWS CLI are not impacted by this change. If you use an AWS SDK or a version of the AWS CLI released prior to February 5, 2015, you should upgrade to the latest version.

Potential Issues

If your system is configured to use a very restricted list of root CAs (for example, if you use certificate pinning), you may be impacted by this migration. In this situation, you must update your pinned certificates to include the Amazon Trust Services CAs.

Adding New Root Certificates

The following sections list the steps you can take to install the Amazon Root CA certificates on your systems if they are not already present.

macOS

To install a new certificate on a macOS server

  1. Download the .pem file for the certificate you want to install from https://www.amazontrust.com/repository.
  2. Change the file extension for the file you downloaded from .pem to .crt.
  3. At the command prompt, type the following command to install the certificate: sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /path/to/certificatename.crt, replacing /path/to/certificatename.crt with the full path to the certificate file.

Windows Server

To install a new certificate on a Windows server

  1. Download the .pem file for the certificate you want to install from https://www.amazontrust.com/repository.
  2. Change the file extension for the file you downloaded from .pem to .crt.
  3. At the command prompt, type the following command to install the certificate: certutil -addstore -f "ROOT" c:\path\to\certificatename.crt, replacing c:\path\to\certificatename.crt with the full path to the certificate file.

Ubuntu

To install a new certificate on an Ubuntu (or similar) server

  1. Download the .pem file for the certificate you want to install from https://www.amazontrust.com/repository.
  2. Change the file extension for the file you downloaded from .pem to .crt.
  3. Copy the certificate file to the directory /usr/local/share/ca-certificates/
  4. At the command prompt, type the following command to update the certificate authority store: sudo update-ca-certificates

Red Hat Enterprise Linux/Fedora/CentOS

To install a new certificate on a Red Hat Enterprise Linux (or similar) server

  1. Download the .pem file for the certificate you want to install from https://www.amazontrust.com/repository.
  2. Change the file extension for the file you downloaded from .pem to .crt.
  3. Copy the certificate file to the directory /etc/pki/ca-trust/source/anchors/
  4. At the command line, type the following command to enable dynamic certificate authority configuration: sudo update-ca-trust force-enable
  5. At the command line, type the following command to update the certificate authority store: sudo update-ca-trust extract

To learn more about this migration, see How to Prepare for AWS’s Move to Its Own Certificate Authority on the AWS Security Blog.

Looking Forward to 2018

Post Syndicated from Let's Encrypt - Free SSL/TLS Certificates original https://letsencrypt.org/2017/12/07/looking-forward-to-2018.html

<p>Let’s Encrypt had a great year in 2017. We more than doubled the number of active (unexpired) certificates we service to 46 million, we just about tripled the number of unique domains we service to 61 million, and we did it all while maintaining a stellar security and compliance track record. Most importantly though, <a href="https://letsencrypt.org/stats/">the Web went from 46% encrypted page loads to 67%</a> according to statistics from Mozilla – a gain of 21 percentage points in a single year – incredible. We’re proud to have contributed to that, and we’d like to thank all of the other people and organizations who also worked hard to create a more secure and privacy-respecting Web.</p>

<p>While we’re proud of what we accomplished in 2017, we are spending most of the final quarter of the year looking forward rather than back. As we wrap up our own planning process for 2018, I’d like to share some of our plans with you, including both the things we’re excited about and the challenges we’ll face. We’ll cover service growth, new features, infrastructure, and finances.</p>

<h1 id="service-growth">Service Growth</h1>

<p>We are planning to double the number of active certificates and unique domains we service in 2018, to 90 million and 120 million, respectively. This anticipated growth is due to continuing high expectations for HTTPS growth in general in 2018.</p>

<p>Let’s Encrypt helps to drive HTTPS adoption by offering a free, easy to use, and globally available option for obtaining the certificates required to enable HTTPS. HTTPS adoption on the Web took off at an unprecedented rate from the day Let’s Encrypt launched to the public.</p>

<p>One of the reasons Let’s Encrypt is so easy to use is that our community has done great work making client software that works well for a wide variety of platforms. We’d like to thank everyone involved in the development of over 60 <a href="https://letsencrypt.org/docs/client-options/">client software options for Let’s Encrypt</a>. We’re particularly excited that support for the ACME protocol and Let’s Encrypt is <a href="https://letsencrypt.org/2017/10/17/acme-support-in-apache-httpd.html">being added to the Apache httpd server</a>.</p>

<p>Other organizations and communities are also doing great work to promote HTTPS adoption, and thus stimulate demand for our services. For example, browsers are starting to make their users more aware of the risks associated with unencrypted HTTP (e.g. <a href="https://blog.mozilla.org/security/2017/01/20/communicating-the-dangers-of-non-secure-http/">Firefox</a>, <a href="https://security.googleblog.com/2017/04/next-steps-toward-more-connection.html">Chrome</a>). Many hosting providers and CDNs are making it easier than ever for all of their customers to use HTTPS. <a href="https://https.cio.gov/">Government</a> <a href="https://www.canada.ca/en/treasury-board-secretariat/services/information-technology/strategic-plan-2017-2021.html#toc8-3-2">agencies</a> are waking up to the need for stronger security to protect constituents. The media community is working to <a href="https://securethe.news/">Secure the News</a>.</p>

<h1 id="new-features">New Features</h1>

<p>We’ve got some exciting features planned for 2018.</p>

<p>First, we’re planning to introduce an ACME v2 protocol API endpoint and <a href="https://letsencrypt.org/2017/07/06/wildcard-certificates-coming-jan-2018.html">support for wildcard certificates</a> along with it. Wildcard certificates will be free and available globally just like our other certificates. We are planning to have a public test API endpoint up by January 4, and we’ve set a date for the full launch: Tuesday, February 27.</p>

<p>Later in 2018 we plan to introduce ECDSA root and intermediate certificates. ECDSA is generally considered to be the future of digital signature algorithms on the Web due to the fact that it is more efficient than RSA. Let’s Encrypt will currently sign ECDSA keys from subscribers, but we sign with the RSA key from one of our intermediate certificates. Once we have an ECDSA root and intermediates, our subscribers will be able to deploy certificate chains which are entirely ECDSA.</p>

<h1 id="infrastructure">Infrastructure</h1>

<p>Our CA infrastructure is capable of issuing millions of certificates per day with multiple redundancy for stability and a wide variety of security safeguards, both physical and logical. Our infrastructure also generates and signs nearly 20 million OCSP responses daily, and serves those responses nearly 2 billion times per day. We expect issuance and OCSP numbers to double in 2018.</p>

<p>Our physical CA infrastructure currently occupies approximately 70 units of rack space, split between two datacenters, consisting primarily of compute servers, storage, HSMs, switches, and firewalls.</p>

<p>When we issue more certificates it puts the most stress on storage for our databases. We regularly invest in more and faster storage for our database servers, and that will continue in 2018.</p>

<p>We’ll need to add a few additional compute servers in 2018, and we’ll also start aging out hardware in 2018 for the first time since we launched. We’ll age out about ten 2u compute servers and replace them with new 1u servers, which will save space and be more energy efficient while providing better reliability and performance.</p>

<p>We’ll also add another infrastructure operations staff member, bringing that team to a total of six people. This is necessary in order to make sure we can keep up with demand while maintaining a high standard for security and compliance. Infrastructure operations staff are systems administrators responsible for building and maintaining all physical and logical CA infrastructure. The team also manages a 24/7/365 on-call schedule and they are primary participants in both security and compliance audits.</p>

<h1 id="finances">Finances</h1>

<p>We pride ourselves on being an efficient organization. In 2018 Let’s Encrypt will secure a large portion of the Web with a budget of only $3.0M. For an overall increase in our budget of only 13%, we will be able to issue and service twice as many certificates as we did in 2017. We believe this represents an incredible value and that contributing to Let’s Encrypt is one of the most effective ways to help create a more secure and privacy-respecting Web.</p>

<p>Our 2018 fundraising efforts are off to a strong start with Platinum sponsorships from Mozilla, Akamai, OVH, Cisco, Google Chrome and the Electronic Frontier Foundation. The Ford Foundation has renewed their grant to Let’s Encrypt as well. We are seeking additional sponsorship and grant assistance to meet our full needs for 2018.</p>

<p>We had originally budgeted $2.91M for 2017 but we’ll likely come in under budget for the year at around $2.65M. The difference between our 2017 expenses of $2.65M and the 2018 budget of $3.0M consists primarily of the additional infrastructure operations costs previously mentioned.</p>

<h1 id="support-let-s-encrypt">Support Let’s Encrypt</h1>

<p>We depend on contributions from our community of users and supporters in order to provide our services. If your company or organization would like to <a href="https://letsencrypt.org/become-a-sponsor/">sponsor</a> Let’s Encrypt please email us at <a href="mailto:[email protected]">[email protected]</a>. We ask that you make an <a href="https://letsencrypt.org/donate/">individual contribution</a> if it is within your means.</p>

<p>We’re grateful for the industry and community support that we receive, and we look forward to continuing to create a more secure and privacy-respecting Web!</p>

Object models

Post Syndicated from Eevee original https://eev.ee/blog/2017/11/28/object-models/

Anonymous asks, with dollars:

More about programming languages!

Well then!

I’ve written before about what I think objects are: state and behavior, which in practice mostly means method calls.

I suspect that the popular impression of what objects are, and also how they should work, comes from whatever C++ and Java happen to do. From that point of view, the whole post above is probably nonsense. If the baseline notion of “object” is a rigid definition woven tightly into the design of two massively popular languages, then it doesn’t even make sense to talk about what “object” should mean — it does mean the features of those languages, and cannot possibly mean anything else.

I think that’s a shame! It piles a lot of baggage onto a fairly simple idea. Polymorphism, for example, has nothing to do with objects — it’s an escape hatch for static type systems. Inheritance isn’t the only way to reuse code between objects, but it’s the easiest and fastest one, so it’s what we get. Frankly, it’s much closer to a speed tradeoff than a fundamental part of the concept.

We could do with more experimentation around how objects work, but that’s impossible in the languages most commonly thought of as object-oriented.

Here, then, is a (very) brief run through the inner workings of objects in four very dynamic languages. I don’t think I really appreciated objects until I’d spent some time with Python, and I hope this can help someone else whet their own appetite.

Python 3

Of the four languages I’m going to touch on, Python will look the most familiar to the Java and C++ crowd. For starters, it actually has a class construct.

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class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __neg__(self):
        return Vector(-self.x, -self.y)

    def __div__(self, denom):
        return Vector(self.x / denom, self.y / denom)

    @property
    def magnitude(self):
        return (self.x ** 2 + self.y ** 2) ** 0.5

    def normalized(self):
        return self / self.magnitude

The __init__ method is an initializer, which is like a constructor but named differently (because the object already exists in a usable form by the time the initializer is called). Operator overloading is done by implementing methods with other special __dunder__ names. Properties can be created with @property, where the @ is syntax for applying a wrapper function to a function as it’s defined. You can do inheritance, even multiply:

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class Foo(A, B, C):
    def bar(self, x, y, z):
        # do some stuff
        super().bar(x, y, z)

Cool, a very traditional object model.

Except… for some details.

Some details

For one, Python objects don’t have a fixed layout. Code both inside and outside the class can add or remove whatever attributes they want from whatever object they want. The underlying storage is just a dict, Python’s mapping type. (Or, rather, something like one. Also, it’s possible to change, which will probably be the case for everything I say here.)

If you create some attributes at the class level, you’ll start to get a peek behind the curtains:

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class Foo:
    values = []

    def add_value(self, value):
        self.values.append(value)

a = Foo()
b = Foo()
a.add_value('a')
print(a.values)  # ['a']
b.add_value('b')
print(b.values)  # ['a', 'b']

The [] assigned to values isn’t a default assigned to each object. In fact, the individual objects don’t know about it at all! You can use vars(a) to get at the underlying storage dict, and you won’t see a values entry in there anywhere.

Instead, values lives on the class, which is a value (and thus an object) in its own right. When Python is asked for self.values, it checks to see if self has a values attribute; in this case, it doesn’t, so Python keeps going and asks the class for one.

Python’s object model is secretly prototypical — a class acts as a prototype, as a shared set of fallback values, for its objects.

In fact, this is also how method calls work! They aren’t syntactically special at all, which you can see by separating the attribute lookup from the call.

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print("abc".startswith("a"))  # True
meth = "abc".startswith
print(meth("a"))  # True

Reading obj.method looks for a method attribute; if there isn’t one on obj, Python checks the class. Here, it finds one: it’s a function from the class body.

Ah, but wait! In the code I just showed, meth seems to “know” the object it came from, so it can’t just be a plain function. If you inspect the resulting value, it claims to be a “bound method” or “built-in method” rather than a function, too. Something funny is going on here, and that funny something is the descriptor protocol.

Descriptors

Python allows attributes to implement their own custom behavior when read from or written to. Such an attribute is called a descriptor. I’ve written about them before, but here’s a quick overview.

If Python looks up an attribute, finds it in a class, and the value it gets has a __get__ method… then instead of using that value, Python will use the return value of its __get__ method.

The @property decorator works this way. The magnitude property in my original example was shorthand for doing this:

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class MagnitudeDescriptor:
    def __get__(self, instance, owner):
        if instance is None:
            return self
        return (instance.x ** 2 + instance.y ** 2) ** 0.5

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    magnitude = MagnitudeDescriptor()

When you ask for somevec.magnitude, Python checks somevec but doesn’t find magnitude, so it consults the class instead. The class does have a magnitude, and it’s a value with a __get__ method, so Python calls that method and somevec.magnitude evaluates to its return value. (The instance is None check is because __get__ is called even if you get the descriptor directly from the class via Vector.magnitude. A descriptor intended to work on instances can’t do anything useful in that case, so the convention is to return the descriptor itself.)

You can also intercept attempts to write to or delete an attribute, and do absolutely whatever you want instead. But note that, similar to operating overloading in Python, the descriptor must be on a class; you can’t just slap one on an arbitrary object and have it work.

This brings me right around to how “bound methods” actually work. Functions are descriptors! The function type implements __get__, and when a function is retrieved from a class via an instance, that __get__ bundles the function and the instance together into a tiny bound method object. It’s essentially:

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class FunctionType:
    def __get__(self, instance, owner):
        if instance is None:
            return self
        return functools.partial(self, instance)

The self passed as the first argument to methods is not special or magical in any way. It’s built out of a few simple pieces that are also readily accessible to Python code.

Note also that because obj.method() is just an attribute lookup and a call, Python doesn’t actually care whether method is a method on the class or just some callable thing on the object. You won’t get the auto-self behavior if it’s on the object, but otherwise there’s no difference.

More attribute access, and the interesting part

Descriptors are one of several ways to customize attribute access. Classes can implement __getattr__ to intervene when an attribute isn’t found on an object; __setattr__ and __delattr__ to intervene when any attribute is set or deleted; and __getattribute__ to implement unconditional attribute access. (That last one is a fantastic way to create accidental recursion, since any attribute access you do within __getattribute__ will of course call __getattribute__ again.)

Here’s what I really love about Python. It might seem like a magical special case that descriptors only work on classes, but it really isn’t. You could implement exactly the same behavior yourself, in pure Python, using only the things I’ve just told you about. Classes are themselves objects, remember, and they are instances of type, so the reason descriptors only work on classes is that type effectively does this:

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class type:
    def __getattribute__(self, name):
        value = super().__getattribute__(name)
        # like all op overloads, __get__ must be on the type, not the instance
        ty = type(value)
        if hasattr(ty, '__get__'):
            # it's a descriptor!  this is a class access so there is no instance
            return ty.__get__(value, None, self)
        else:
            return value

You can even trivially prove to yourself that this is what’s going on by skipping over types behavior:

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class Descriptor:
    def __get__(self, instance, owner):
        print('called!')

class Foo:
    bar = Descriptor()

Foo.bar  # called!
type.__getattribute__(Foo, 'bar')  # called!
object.__getattribute__(Foo, 'bar')  # ...

And that’s not all! The mysterious super function, used to exhaustively traverse superclass method calls even in the face of diamond inheritance, can also be expressed in pure Python using these primitives. You could write your own superclass calling convention and use it exactly the same way as super.

This is one of the things I really like about Python. Very little of it is truly magical; virtually everything about the object model exists in the types rather than the language, which means virtually everything can be customized in pure Python.

Class creation and metaclasses

A very brief word on all of this stuff, since I could talk forever about Python and I have three other languages to get to.

The class block itself is fairly interesting. It looks like this:

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class Name(*bases, **kwargs):
    # code

I’ve said several times that classes are objects, and in fact the class block is one big pile of syntactic sugar for calling type(...) with some arguments to create a new type object.

The Python documentation has a remarkably detailed description of this process, but the gist is:

  • Python determines the type of the new class — the metaclass — by looking for a metaclass keyword argument. If there isn’t one, Python uses the “lowest” type among the provided base classes. (If you’re not doing anything special, that’ll just be type, since every class inherits from object and object is an instance of type.)

  • Python executes the class body. It gets its own local scope, and any assignments or method definitions go into that scope.

  • Python now calls type(name, bases, attrs, **kwargs). The name is whatever was right after class; the bases are position arguments; and attrs is the class body’s local scope. (This is how methods and other class attributes end up on the class.) The brand new type is then assigned to Name.

Of course, you can mess with most of this. You can implement __prepare__ on a metaclass, for example, to use a custom mapping as storage for the local scope — including any reads, which allows for some interesting shenanigans. The only part you can’t really implement in pure Python is the scoping bit, which has a couple extra rules that make sense for classes. (In particular, functions defined within a class block don’t close over the class body; that would be nonsense.)

Object creation

Finally, there’s what actually happens when you create an object — including a class, which remember is just an invocation of type(...).

Calling Foo(...) is implemented as, well, a call. Any type can implement calls with the __call__ special method, and you’ll find that type itself does so. It looks something like this:

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# oh, a fun wrinkle that's hard to express in pure python: type is a class, so
# it's an instance of itself
class type:
    def __call__(self, *args, **kwargs):
        # remember, here 'self' is a CLASS, an instance of type.
        # __new__ is a true constructor: object.__new__ allocates storage
        # for a new blank object
        instance = self.__new__(self, *args, **kwargs)
        # you can return whatever you want from __new__ (!), and __init__
        # is only called on it if it's of the right type
        if isinstance(instance, self):
            instance.__init__(*args, **kwargs)
        return instance

Again, you can trivially confirm this by asking any type for its __call__ method. Assuming that type doesn’t implement __call__ itself, you’ll get back a bound version of types implementation.

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>>> list.__call__
<method-wrapper '__call__' of type object at 0x7fafb831a400>

You can thus implement __call__ in your own metaclass to completely change how subclasses are created — including skipping the creation altogether, if you like.

And… there’s a bunch of stuff I haven’t even touched on.

The Python philosophy

Python offers something that, on the surface, looks like a “traditional” class/object model. Under the hood, it acts more like a prototypical system, where failed attribute lookups simply defer to a superclass or metaclass.

The language also goes to almost superhuman lengths to expose all of its moving parts. Even the prototypical behavior is an implementation of __getattribute__ somewhere, which you are free to completely replace in your own types. Proxying and delegation are easy.

Also very nice is that these features “bundle” well, by which I mean a library author can do all manner of convoluted hijinks, and a consumer of that library doesn’t have to see any of it or understand how it works. You only need to inherit from a particular class (which has a metaclass), or use some descriptor as a decorator, or even learn any new syntax.

This meshes well with Python culture, which is pretty big on the principle of least surprise. These super-advanced features tend to be tightly confined to single simple features (like “makes a weak attribute“) or cordoned with DSLs (e.g., defining a form/struct/database table with a class body). In particular, I’ve never seen a metaclass in the wild implement its own __call__.

I have mixed feelings about that. It’s probably a good thing overall that the Python world shows such restraint, but I wonder if there are some very interesting possibilities we’re missing out on. I implemented a metaclass __call__ myself, just once, in an entity/component system that strove to minimize fuss when communicating between components. It never saw the light of day, but I enjoyed seeing some new things Python could do with the same relatively simple syntax. I wouldn’t mind seeing, say, an object model based on composition (with no inheritance) built atop Python’s primitives.

Lua

Lua doesn’t have an object model. Instead, it gives you a handful of very small primitives for building your own object model. This is pretty typical of Lua — it’s a very powerful language, but has been carefully constructed to be very small at the same time. I’ve never encountered anything else quite like it, and “but it starts indexing at 1!” really doesn’t do it justice.

The best way to demonstrate how objects work in Lua is to build some from scratch. We need two key features. The first is metatables, which bear a passing resemblance to Python’s metaclasses.

Tables and metatables

The table is Lua’s mapping type and its primary data structure. Keys can be any value other than nil. Lists are implemented as tables whose keys are consecutive integers starting from 1. Nothing terribly surprising. The dot operator is sugar for indexing with a string key.

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local t = { a = 1, b = 2 }
print(t['a'])  -- 1
print(t.b)  -- 2
t.c = 3
print(t['c'])  -- 3

A metatable is a table that can be associated with another value (usually another table) to change its behavior. For example, operator overloading is implemented by assigning a function to a special key in a metatable.

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local t = { a = 1, b = 2 }
--print(t + 0)  -- error: attempt to perform arithmetic on a table value

local mt = {
    __add = function(left, right)
        return 12
    end,
}
setmetatable(t, mt)
print(t + 0)  -- 12

Now, the interesting part: one of the special keys is __index, which is consulted when the base table is indexed by a key it doesn’t contain. Here’s a table that claims every key maps to itself.

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local t = {}
local mt = {
    __index = function(table, key)
        return key
    end,
}
setmetatable(t, mt)
print(t.foo)  -- foo
print(t.bar)  -- bar
print(t[3])  -- 3

__index doesn’t have to be a function, either. It can be yet another table, in which case that table is simply indexed with the key. If the key still doesn’t exist and that table has a metatable with an __index, the process repeats.

With this, it’s easy to have several unrelated tables that act as a single table. Call the base table an object, fill the __index table with functions and call it a class, and you have half of an object system. You can even get prototypical inheritance by chaining __indexes together.

At this point things are a little confusing, since we have at least three tables going on, so here’s a diagram. Keep in mind that Lua doesn’t actually have anything called an “object”, “class”, or “method” — those are just convenient nicknames for a particular structure we might build with Lua’s primitives.

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                    ╔═══════════╗        ...
                    ║ metatable ║         ║
                    ╟───────────╢   ┌─────╨───────────────────────┐
                    ║ __index   ╫───┤ lookup table ("superclass") │
                    ╚═══╦═══════╝   ├─────────────────────────────┤
  ╔═══════════╗         ║           │ some other method           ┼─── function() ... end
  ║ metatable ║         ║           └─────────────────────────────┘
  ╟───────────╢   ┌─────╨──────────────────┐
  ║ __index   ╫───┤ lookup table ("class") │
  ╚═══╦═══════╝   ├────────────────────────┤
      ║           │ some method            ┼─── function() ... end
      ║           └────────────────────────┘
┌─────╨─────────────────┐
│ base table ("object") │
└───────────────────────┘

Note that a metatable is not the same as a class; it defines behavior, not methods. Conversely, if you try to use a class directly as a metatable, it will probably not do much. (This is pretty different from e.g. Python, where operator overloads are just methods with funny names. One nice thing about the Lua approach is that you can keep interface-like functionality separate from methods, and avoid clogging up arbitrary objects’ namespaces. You could even use a dummy table as a key and completely avoid name collisions.)

Anyway, code!

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local class = {
    foo = function(a)
        print("foo got", a)
    end,
}
local mt = { __index = class }
-- setmetatable returns its first argument, so this is nice shorthand
local obj1 = setmetatable({}, mt)
local obj2 = setmetatable({}, mt)
obj1.foo(7)  -- foo got 7
obj2.foo(9)  -- foo got 9

Wait, wait, hang on. Didn’t I call these methods? How do they get at the object? Maybe Lua has a magical this variable?

Methods, sort of

Not quite, but this is where the other key feature comes in: method-call syntax. It’s the lightest touch of sugar, just enough to have method invocation.

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-- note the colon!
a:b(c, d, ...)

-- exactly equivalent to this
-- (except that `a` is only evaluated once)
a.b(a, c, d, ...)

-- which of course is really this
a["b"](a, c, d, ...)

Now we can write methods that actually do something.

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local class = {
    bar = function(self)
        print("our score is", self.score)
    end,
}
local mt = { __index = class }
local obj1 = setmetatable({ score = 13 }, mt)
local obj2 = setmetatable({ score = 25 }, mt)
obj1:bar()  -- our score is 13
obj2:bar()  -- our score is 25

And that’s all you need. Much like Python, methods and data live in the same namespace, and Lua doesn’t care whether obj:method() finds a function on obj or gets one from the metatable’s __index. Unlike Python, the function will be passed self either way, because self comes from the use of : rather than from the lookup behavior.

(Aside: strictly speaking, any Lua value can have a metatable — and if you try to index a non-table, Lua will always consult the metatable’s __index. Strings all have the string library as a metatable, so you can call methods on them: try ("%s %s"):format(1, 2). I don’t think Lua lets user code set the metatable for non-tables, so this isn’t that interesting, but if you’re writing Lua bindings from C then you can wrap your pointers in metatables to give them methods implemented in C.)

Bringing it all together

Of course, writing all this stuff every time is a little tedious and error-prone, so instead you might want to wrap it all up inside a little function. No problem.

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local function make_object(body)
    -- create a metatable
    local mt = { __index = body }
    -- create a base table to serve as the object itself
    local obj = setmetatable({}, mt)
    -- and, done
    return obj
end

-- you can leave off parens if you're only passing in 
local Dog = {
    -- this acts as a "default" value; if obj.barks is missing, __index will
    -- kick in and find this value on the class.  but if obj.barks is assigned
    -- to, it'll go in the object and shadow the value here.
    barks = 0,

    bark = function(self)
        self.barks = self.barks + 1
        print("woof!")
    end,
}

local mydog = make_object(Dog)
mydog:bark()  -- woof!
mydog:bark()  -- woof!
mydog:bark()  -- woof!
print(mydog.barks)  -- 3
print(Dog.barks)  -- 0

It works, but it’s fairly barebones. The nice thing is that you can extend it pretty much however you want. I won’t reproduce an entire serious object system here — lord knows there are enough of them floating around — but the implementation I have for my LÖVE games lets me do this:

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local Animal = Object:extend{
    cries = 0,
}

-- called automatically by Object
function Animal:init()
    print("whoops i couldn't think of anything interesting to put here")
end

-- this is just nice syntax for adding a first argument called 'self', then
-- assigning this function to Animal.cry
function Animal:cry()
    self.cries = self.cries + 1
end

local Cat = Animal:extend{}

function Cat:cry()
    print("meow!")
    Cat.__super.cry(self)
end

local cat = Cat()
cat:cry()  -- meow!
cat:cry()  -- meow!
print(cat.cries)  -- 2

When I say you can extend it however you want, I mean that. I could’ve implemented Python (2)-style super(Cat, self):cry() syntax; I just never got around to it. I could even make it work with multiple inheritance if I really wanted to — or I could go the complete opposite direction and only implement composition. I could implement descriptors, customizing the behavior of individual table keys. I could add pretty decent syntax for composition/proxying. I am trying very hard to end this section now.

The Lua philosophy

Lua’s philosophy is to… not have a philosophy? It gives you the bare minimum to make objects work, and you can do absolutely whatever you want from there. Lua does have something resembling prototypical inheritance, but it’s not so much a first-class feature as an emergent property of some very simple tools. And since you can make __index be a function, you could avoid the prototypical behavior and do something different entirely.

The very severe downside, of course, is that you have to find or build your own object system — which can get pretty confusing very quickly, what with the multiple small moving parts. Third-party code may also have its own object system with subtly different behavior. (Though, in my experience, third-party code tries very hard to avoid needing an object system at all.)

It’s hard to say what the Lua “culture” is like, since Lua is an embedded language that’s often a little different in each environment. I imagine it has a thousand millicultures, instead. I can say that the tedium of building my own object model has led me into something very “traditional”, with prototypical inheritance and whatnot. It’s partly what I’m used to, but it’s also just really dang easy to get working.

Likewise, while I love properties in Python and use them all the dang time, I’ve yet to use a single one in Lua. They wouldn’t be particularly hard to add to my object model, but having to add them myself (or shop around for an object model with them and also port all my code to use it) adds a huge amount of friction. I’ve thought about designing an interesting ECS with custom object behavior, too, but… is it really worth the effort? For all the power and flexibility Lua offers, the cost is that by the time I have something working at all, I’m too exhausted to actually use any of it.

JavaScript

JavaScript is notable for being preposterously heavily used, yet not having a class block.

Well. Okay. Yes. It has one now. It didn’t for a very long time, and even the one it has now is sugar.

Here’s a vector class again:

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class Vector {
    constructor(x, y) {
        this.x = x;
        this.y = y;
    }

    get magnitude() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    }

    dot(other) {
        return this.x * other.x + this.y * other.y;
    }
}

In “classic” JavaScript, this would be written as:

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function Vector(x, y) {
    this.x = x;
    this.y = y;
}

Object.defineProperty(Vector.prototype, 'magnitude', {
    configurable: true,
    enumerable: true,
    get: function() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    },
});


Vector.prototype.dot = function(other) {
    return this.x * other.x + this.y * other.y;
};

Hm, yes. I can see why they added class.

The JavaScript model

In JavaScript, a new type is defined in terms of a function, which is its constructor.

Right away we get into trouble here. There is a very big difference between these two invocations, which I actually completely forgot about just now after spending four hours writing about Python and Lua:

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let vec = Vector(3, 4);
let vec = new Vector(3, 4);

The first calls the function Vector. It assigns some properties to this, which here is going to be window, so now you have a global x and y. It then returns nothing, so vec is undefined.

The second calls Vector with this set to a new empty object, then evaluates to that object. The result is what you’d actually expect.

(You can detect this situation with the strange new.target expression, but I have never once remembered to do so.)

From here, we have true, honest-to-god, first-class prototypical inheritance. The word “prototype” is even right there. When you write this:

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vec.dot(vec2)

JavaScript will look for dot on vec and (presumably) not find it. It then consults vecs prototype, an object you can see for yourself by using Object.getPrototypeOf(). Since vec is a Vector, its prototype is Vector.prototype.

I stress that Vector.prototype is not the prototype for Vector. It’s the prototype for instances of Vector.

(I say “instance”, but the true type of vec here is still just object. If you want to find Vector, it’s automatically assigned to the constructor property of its own prototype, so it’s available as vec.constructor.)

Of course, Vector.prototype can itself have a prototype, in which case the process would continue if dot were not found. A common (and, arguably, very bad) way to simulate single inheritance is to set Class.prototype to an instance of a superclass to get the prototype right, then tack on the methods for Class. Nowadays we can do Object.create(Superclass.prototype).

Now that I’ve been through Python and Lua, though, this isn’t particularly surprising. I kinda spoiled it.

I suppose one difference in JavaScript is that you can tack arbitrary attributes directly onto Vector all you like, and they will remain invisible to instances since they aren’t in the prototype chain. This is kind of backwards from Lua, where you can squirrel stuff away in the metatable.

Another difference is that every single object in JavaScript has a bunch of properties already tacked on — the ones in Object.prototype. Every object (and by “object” I mean any mapping) has a prototype, and that prototype defaults to Object.prototype, and it has a bunch of ancient junk like isPrototypeOf.

(Nit: it’s possible to explicitly create an object with no prototype via Object.create(null).)

Like Lua, and unlike Python, JavaScript doesn’t distinguish between keys found on an object and keys found via a prototype. Properties can be defined on prototypes with Object.defineProperty(), but that works just as well directly on an object, too. JavaScript doesn’t have a lot of operator overloading, but some things like Symbol.iterator also work on both objects and prototypes.

About this

You may, at this point, be wondering what this is. Unlike Lua and Python (and the last language below), this is a special built-in value — a context value, invisibly passed for every function call.

It’s determined by where the function came from. If the function was the result of an attribute lookup, then this is set to the object containing that attribute. Otherwise, this is set to the global object, window. (You can also set this to whatever you want via the call method on functions.)

This decision is made lexically, i.e. from the literal source code as written. There are no Python-style bound methods. In other words:

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// this = obj
obj.method()
// this = window
let meth = obj.method
meth()

Also, because this is reassigned on every function call, it cannot be meaningfully closed over, which makes using closures within methods incredibly annoying. The old approach was to assign this to some other regular name like self (which got syntax highlighting since it’s also a built-in name in browsers); then we got Function.bind, which produced a callable thing with a fixed context value, which was kind of nice; and now finally we have arrow functions, which explicitly close over the current this when they’re defined and don’t change it when called. Phew.

Class syntax

I already showed class syntax, and it’s really just one big macro for doing all the prototype stuff The Right Way. It even prevents you from calling the type without new. The underlying model is exactly the same, and you can inspect all the parts.

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class Vector { ... }

console.log(Vector.prototype);  // { dot: ..., magnitude: ..., ... }
let vec = new Vector(3, 4);
console.log(Object.getPrototypeOf(vec));  // same as Vector.prototype

// i don't know why you would subclass vector but let's roll with it
class Vectest extends Vector { ... }

console.log(Vectest.prototype);  // { ... }
console.log(Object.getPrototypeOf(Vectest.prototype))  // same as Vector.prototype

Alas, class syntax has a couple shortcomings. You can’t use the class block to assign arbitrary data to either the type object or the prototype — apparently it was deemed too confusing that mutations would be shared among instances. Which… is… how prototypes work. How Python works. How JavaScript itself, one of the most popular languages of all time, has worked for twenty-two years. Argh.

You can still do whatever assignment you want outside of the class block, of course. It’s just a little ugly, and not something I’d think to look for with a sugary class.

A more subtle result of this behavior is that a class block isn’t quite the same syntax as an object literal. The check for data isn’t a runtime thing; class Foo { x: 3 } fails to parse. So JavaScript now has two largely but not entirely identical styles of key/value block.

Attribute access

Here’s where things start to come apart at the seams, just a little bit.

JavaScript doesn’t really have an attribute protocol. Instead, it has two… extension points, I suppose.

One is Object.defineProperty, seen above. For common cases, there’s also the get syntax inside a property literal, which does the same thing. But unlike Python’s @property, these aren’t wrappers around some simple primitives; they are the primitives. JavaScript is the only language of these four to have “property that runs code on access” as a completely separate first-class concept.

If you want to intercept arbitrary attribute access (and some kinds of operators), there’s a completely different primitive: the Proxy type. It doesn’t let you intercept attribute access or operators; instead, it produces a wrapper object that supports interception and defers to the wrapped object by default.

It’s cool to see composition used in this way, but also, extremely weird. If you want to make your own type that overloads in or calling, you have to return a Proxy that wraps your own type, rather than actually returning your own type. And (unlike the other three languages in this post) you can’t return a different type from a constructor, so you have to throw that away and produce objects only from a factory. And instanceof would be broken, but you can at least fix that with Symbol.hasInstance — which is really operator overloading, implement yet another completely different way.

I know the design here is a result of legacy and speed — if any object could intercept all attribute access, then all attribute access would be slowed down everywhere. Fair enough. It still leaves the surface area of the language a bit… bumpy?

The JavaScript philosophy

It’s a little hard to tell. The original idea of prototypes was interesting, but it was hidden behind some very awkward syntax. Since then, we’ve gotten a bunch of extra features awkwardly bolted on to reflect the wildly varied things the built-in types and DOM API were already doing. We have class syntax, but it’s been explicitly designed to avoid exposing the prototype parts of the model.

I admit I don’t do a lot of heavy JavaScript, so I might just be overlooking it, but I’ve seen virtually no code that makes use of any of the recent advances in object capabilities. Forget about custom iterators or overloading call; I can’t remember seeing any JavaScript in the wild that even uses properties yet. I don’t know if everyone’s waiting for sufficient browser support, nobody knows about them, or nobody cares.

The model has advanced recently, but I suspect JavaScript is still shackled to its legacy of “something about prototypes, I don’t really get it, just copy the other code that’s there” as an object model. Alas! Prototypes are so good. Hopefully class syntax will make it a bit more accessible, as it has in Python.

Perl 5

Perl 5 also doesn’t have an object system and expects you to build your own. But where Lua gives you two simple, powerful tools for building one, Perl 5 feels more like a puzzle with half the pieces missing. Clearly they were going for something, but they only gave you half of it.

In brief, a Perl object is a reference that has been blessed with a package.

I need to explain a few things. Honestly, one of the biggest problems with the original Perl object setup was how many strange corners and unique jargon you had to understand just to get off the ground.

(If you want to try running any of this code, you should stick a use v5.26; as the first line. Perl is very big on backwards compatibility, so you need to opt into breaking changes, and even the mundane say builtin is behind a feature gate.)

References

A reference in Perl is sort of like a pointer, but its main use is very different. See, Perl has the strange property that its data structures try very hard to spill their contents all over the place. Despite having dedicated syntax for arrays — @foo is an array variable, distinct from the single scalar variable $foo — it’s actually impossible to nest arrays.

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my @foo = (1, 2, 3, 4);
my @bar = (@foo, @foo);
# @bar is now a flat list of eight items: 1, 2, 3, 4, 1, 2, 3, 4

The idea, I guess, is that an array is not one thing. It’s not a container, which happens to hold multiple things; it is multiple things. Anywhere that expects a single value, such as an array element, cannot contain an array, because an array fundamentally is not a single value.

And so we have “references”, which are a form of indirection, but also have the nice property that they’re single values. They add containment around arrays, and in general they make working with most of Perl’s primitive types much more sensible. A reference to a variable can be taken with the \ operator, or you can use [ ... ] and { ... } to directly create references to anonymous arrays or hashes.

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my @foo = (1, 2, 3, 4);
my @bar = (\@foo, \@foo);
# @bar is now a nested list of two items: [1, 2, 3, 4], [1, 2, 3, 4]

(Incidentally, this is the sole reason I initially abandoned Perl for Python. Non-trivial software kinda requires nesting a lot of data structures, so you end up with references everywhere, and the syntax for going back and forth between a reference and its contents is tedious and ugly.)

A Perl object must be a reference. Perl doesn’t care what kind of reference — it’s usually a hash reference, since hashes are a convenient place to store arbitrary properties, but it could just as well be a reference to an array, a scalar, or even a sub (i.e. function) or filehandle.

I’m getting a little ahead of myself. First, the other half: blessing and packages.

Packages and blessing

Perl packages are just namespaces. A package looks like this:

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package Foo::Bar;

sub quux {
    say "hi from quux!";
}

# now Foo::Bar::quux() can be called from anywhere

Nothing shocking, right? It’s just a named container. A lot of the details are kind of weird, like how a package exists in some liminal quasi-value space, but the basic idea is a Bag Of Stuff.

The final piece is “blessing,” which is Perl’s funny name for binding a package to a reference. A very basic class might look like this:

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package Vector;

# the name 'new' is convention, not special
sub new {
    # perl argument passing is weird, don't ask
    my ($class, $x, $y) = @_;

    # create the object itself -- here, unusually, an array reference makes sense
    my $self = [ $x, $y ];

    # associate the package with that reference
    # note that $class here is just the regular string, 'Vector'
    bless $self, $class;

    return $self;
}

sub x {
    my ($self) = @_;
    return $self->[0];
}

sub y {
    my ($self) = @_;
    return $self->[1];
}

sub magnitude {
    my ($self) = @_;
    return sqrt($self->x ** 2 + $self->y ** 2);
}

# switch back to the "default" package
package main;

# -> is method call syntax, which passes the invocant as the first argument;
# for a package, that's just the package name
my $vec = Vector->new(3, 4);
say $vec->magnitude;  # 5

A few things of note here. First, $self->[0] has nothing to do with objects; it’s normal syntax for getting the value of a index 0 out of an array reference called $self. (Most classes are based on hashrefs and would use $self->{value} instead.) A blessed reference is still a reference and can be treated like one.

In general, -> is Perl’s dereferencey operator, but its exact behavior depends on what follows. If it’s followed by brackets, then it’ll apply the brackets to the thing in the reference: ->{} to index a hash reference, ->[] to index an array reference, and ->() to call a function reference.

But if -> is followed by an identifier, then it’s a method call. For packages, that means calling a function in the package and passing the package name as the first argument. For objects — blessed references — that means calling a function in the associated package and passing the object as the first argument.

This is a little weird! A blessed reference is a superposition of two things: its normal reference behavior, and some completely orthogonal object behavior. Also, object behavior has no notion of methods vs data; it only knows about methods. Perl lets you omit parentheses in a lot of places, including when calling a method with no arguments, so $vec->magnitude is really $vec->magnitude().

Perl’s blessing bears some similarities to Lua’s metatables, but ultimately Perl is much closer to Ruby’s “message passing” approach than the above three languages’ approaches of “get me something and maybe it’ll be callable”. (But this is no surprise — Ruby is a spiritual successor to Perl 5.)

All of this leads to one little wrinkle: how do you actually expose data? Above, I had to write x and y methods. Am I supposed to do that for every single attribute on my type?

Yes! But don’t worry, there are third-party modules to help with this incredibly fundamental task. Take Class::Accessor::Fast, so named because it’s faster than Class::Accessor:

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package Foo;
use base qw(Class::Accessor::Fast);
__PACKAGE__->mk_accessors(qw(fred wilma barney));

(__PACKAGE__ is the lexical name of the current package; qw(...) is a list literal that splits its contents on whitespace.)

This assumes you’re using a hashref with keys of the same names as the attributes. $obj->fred will return the fred key from your hashref, and $obj->fred(4) will change it to 4.

You also, somewhat bizarrely, have to inherit from Class::Accessor::Fast. Speaking of which,

Inheritance

Inheritance is done by populating the package-global @ISA array with some number of (string) names of parent packages. Most code instead opts to write use base ...;, which does the same thing. Or, more commonly, use parent ...;, which… also… does the same thing.

Every package implicitly inherits from UNIVERSAL, which can be freely modified by Perl code.

A method can call its superclass method with the SUPER:: pseudo-package:

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sub foo {
    my ($self) = @_;
    $self->SUPER::foo;
}

However, this does a depth-first search, which means it almost certainly does the wrong thing when faced with multiple inheritance. For a while the accepted solution involved a third-party module, but Perl eventually grew an alternative you have to opt into: C3, which may be more familiar to you as the order Python uses.

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use mro 'c3';

sub foo {
    my ($self) = @_;
    $self->next::method;
}

Offhand, I’m not actually sure how next::method works, seeing as it was originally implemented in pure Perl code. I suspect it involves peeking at the caller’s stack frame. If so, then this is a very different style of customizability from e.g. Python — the MRO was never intended to be pluggable, and the use of a special pseudo-package means it isn’t really, but someone was determined enough to make it happen anyway.

Operator overloading and whatnot

Operator overloading looks a little weird, though really it’s pretty standard Perl.

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package MyClass;

use overload '+' => \&_add;

sub _add {
    my ($self, $other, $swap) = @_;
    ...
}

use overload here is a pragma, where “pragma” means “regular-ass module that does some wizardry when imported”.

\&_add is how you get a reference to the _add sub so you can pass it to the overload module. If you just said &_add or _add, that would call it.

And that’s it; you just pass a map of operators to functions to this built-in module. No worry about name clashes or pollution, which is pretty nice. You don’t even have to give references to functions that live in the package, if you don’t want them to clog your namespace; you could put them in another package, or even inline them anonymously.

One especially interesting thing is that Perl lets you overload every operator. Perl has a lot of operators. It considers some math builtins like sqrt and trig functions to be operators, or at least operator-y enough that you can overload them. You can also overload the “file text” operators, such as -e $path to test whether a file exists. You can overload conversions, including implicit conversion to a regex. And most fascinating to me, you can overload dereferencing — that is, the thing Perl does when you say $hashref->{key} to get at the underlying hash. So a single object could pretend to be references of multiple different types, including a subref to implement callability. Neat.

Somewhat related: you can overload basic operators (indexing, etc.) on basic types (not references!) with the tie function, which is designed completely differently and looks for methods with fixed names. Go figure.

You can intercept calls to nonexistent methods by implementing a function called AUTOLOAD, within which the $AUTOLOAD global will contain the name of the method being called. Originally this feature was, I think, intended for loading binary components or large libraries on-the-fly only when needed, hence the name. Offhand I’m not sure I ever saw it used the way __getattr__ is used in Python.

Is there a way to intercept all method calls? I don’t think so, but it is Perl, so I must be forgetting something.

Actually no one does this any more

Like a decade ago, a council of elder sages sat down and put together a whole whizbang system that covers all of it: Moose.

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package Vector;
use Moose;

has x => (is => 'rw', isa => 'Int');
has y => (is => 'rw', isa => 'Int');

sub magnitude {
    my ($self) = @_;
    return sqrt($self->x ** 2 + $self->y ** 2);
}

Moose has its own way to do pretty much everything, and it’s all built on the same primitives. Moose also adds metaclasses, somehow, despite that the underlying model doesn’t actually support them? I’m not entirely sure how they managed that, but I do remember doing some class introspection with Moose and it was much nicer than the built-in way.

(If you’re wondering, the built-in way begins with looking at the hash called %Vector::. No, that’s not a typo.)

I really cannot stress enough just how much stuff Moose does, but I don’t want to delve into it here since Moose itself is not actually the language model.

The Perl philosophy

I hope you can see what I meant with what I first said about Perl, now. It has multiple inheritance with an MRO, but uses the wrong one by default. It has extensive operator overloading, which looks nothing like how inheritance works, and also some of it uses a totally different mechanism with special method names instead. It only understands methods, not data, leaving you to figure out accessors by hand.

There’s 70% of an object system here with a clear general design it was gunning for, but none of the pieces really look anything like each other. It’s weird, in a distinctly Perl way.

The result is certainly flexible, at least! It’s especially cool that you can use whatever kind of reference you want for storage, though even as I say that, I acknowledge it’s no different from simply subclassing list or something in Python. It feels different in Perl, but maybe only because it looks so different.

I haven’t written much Perl in a long time, so I don’t know what the community is like any more. Moose was already ubiquitous when I left, which you’d think would let me say “the community mostly focuses on the stuff Moose can do” — but even a decade ago, Moose could already do far more than I had ever seen done by hand in Perl. It’s always made a big deal out of roles (read: interfaces), for instance, despite that I’d never seen anyone care about them in Perl before Moose came along. Maybe their presence in Moose has made them more popular? Who knows.

Also, I wrote Perl seriously, but in the intervening years I’ve only encountered people who only ever used Perl for one-offs. Maybe it’ll come as a surprise to a lot of readers that Perl has an object model at all.

End

Well, that was fun! I hope any of that made sense.

Special mention goes to Rust, which doesn’t have an object model you can fiddle with at runtime, but does do things a little differently.

It’s been really interesting thinking about how tiny differences make a huge impact on what people do in practice. Take the choice of storage in Perl versus Python. Perl’s massively common URI class uses a string as the storage, nothing else; I haven’t seen anything like that in Python aside from markupsafe, which is specifically designed as a string type. I would guess this is partly because Perl makes you choose — using a hashref is an obvious default, but you have to make that choice one way or the other. In Python (especially 3), inheriting from object and getting dict-based storage is the obvious thing to do; the ability to use another type isn’t quite so obvious, and doing it “right” involves a tiny bit of extra work.

Or, consider that Lua could have descriptors, but the extra bit of work (especially design work) has been enough of an impediment that I’ve never implemented them. I don’t think the object implementations I’ve looked at have included them, either. Super weird!

In that light, it’s only natural that objects would be so strongly associated with the features Java and C++ attach to them. I think that makes it all the more important to play around! Look at what Moose has done. No, really, you should bear in mind my description of how Perl does stuff and flip through the Moose documentation. It’s amazing what they’ve built.