Tag Archives: maninthemiddleattacks

Critical Windows Vulnerability Discovered by NSA

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/01/critical_window.html

Yesterday’s Microsoft Windows patches included a fix for a critical vulnerability in the system’s crypto library.

A spoofing vulnerability exists in the way Windows CryptoAPI (Crypt32.dll) validates Elliptic Curve Cryptography (ECC) certificates.

An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source. The user would have no way of knowing the file was malicious, because the digital signature would appear to be from a trusted provider.

A successful exploit could also allow the attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software.

That’s really bad, and you should all patch your system right now, before you finish reading this blog post.

This is a zero-day vulnerability, meaning that it was not detected in the wild before the patch was released. It was discovered by security researchers. Interestingly, it was discovered by NSA security researchers, and the NSA security advisory gives a lot more information about it than the Microsoft advisory does.

Exploitation of the vulnerability allows attackers to defeat trusted network connections and deliver executable code while appearing as legitimately trusted entities. Examples where validation of trust may be impacted include:

  • HTTPS connections
  • Signed files and emails
  • Signed executable code launched as user-mode processes

The vulnerability places Windows endpoints at risk to a broad range of exploitation vectors. NSA assesses the vulnerability to be severe and that sophisticated cyber actors will understand the underlying flaw very quickly and, if exploited, would render the previously mentioned platforms as fundamentally vulnerable.The consequences of not patching the vulnerability are severe and widespread. Remote exploitation tools will likely be made quickly and widely available.Rapid adoption of the patch is the only known mitigation at this time and should be the primary focus for all network owners.

Early yesterday morning, NSA’s Cybersecurity Directorate head Anne Neuberger hosted a media call where she talked about the vulnerability and — to my shock — took questions from the attendees. According to her, the NSA discovered this vulnerability as part of its security research. (If it found it in some other nation’s cyberweapons stash — my personal favorite theory — she declined to say.) She did not answer when asked how long ago the NSA discovered the vulnerability. She said that this is not the first time the NSA sent Microsoft a vulnerability to fix, but it was the first time it has publicly taken credit for the discovery. The reason is that the NSA is trying to rebuild trust with the security community, and this disclosure is a result of its new initiative to share findings more quickly and more often.

Barring any other information, I would take the NSA at its word here. So, good for it.

And — seriously — patch your systems now: Windows 10 and Windows Server 2016/2019. Assume that this vulnerability has already been weaponized, probably by criminals and certainly by major governments. Even assume that the NSA is using this vulnerability — why wouldn’t it?

Ars Technica article. Wired article. CERT advisory.

EDITED TO ADD: Washington Post article.

EDITED TO ADD (1/16): The attack was demonstrated in less than 24 hours.

Brian Krebs blog post.

The NSA Warns of TLS Inspection

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2019/11/the_nsa_warns_o.html

The NSA has released a security advisory warning of the dangers of TLS inspection:

Transport Layer Security Inspection (TLSI), also known as TLS break and inspect, is a security process that allows enterprises to decrypt traffic, inspect the decrypted content for threats, and then re-encrypt the traffic before it enters or leaves the network. Introducing this capability into an enterprise enhances visibility within boundary security products, but introduces new risks. These risks, while not inconsequential, do have mitigations.

[…]

The primary risk involved with TLSI’s embedded CA is the potential abuse of the CA to issue unauthorized certificates trusted by the TLS clients. Abuse of a trusted CA can allow an adversary to sign malicious code to bypass host IDS/IPSs or to deploy malicious services that impersonate legitimate enterprise services to the hosts.

[…]

A further risk of introducing TLSI is that an adversary can focus their exploitation efforts on a single device where potential traffic of interest is decrypted, rather than try to exploit each location where the data is stored.Setting a policy to enforce that traffic is decrypted and inspected only as authorized, and ensuring that decrypted traffic is contained in an out-of-band, isolated segment of the network prevents unauthorized access to the decrypted traffic.

[…]

To minimize the risks described above, breaking and inspecting TLS traffic should only be conducted once within the enterprise network. Redundant TLSI, wherein a client-server traffic flow is decrypted, inspected, and re-encrypted by one forward proxy and is then forwarded to a second forward proxy for more of the same,should not be performed.Inspecting multiple times can greatly complicate diagnosing network issues with TLS traffic. Also, multi-inspection further obscures certificates when trying to ascertain whether a server should be trusted. In this case, the “outermost” proxy makes the decisions on what server certificates or CAs should be trusted and is the only location where certificate pinning can be performed.Finally, a single TLSI implementation is sufficient for detecting encrypted traffic threats; additional TLSI will have access to the same traffic. If the first TLSI implementation detected a threat, killed the session, and dropped the traffic, then additional TLSI implementations would be rendered useless since they would not even receive the dropped traffic for further inspection. Redundant TLSI increases the risk surface, provides additional opportunities for adversaries to gain unauthorized access to decrypted traffic, and offers no additional benefits.

Nothing surprising or novel. No operational information about who might be implementing these attacks. No classified information revealed.

News article.

New DNS Hijacking Attacks

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2019/04/new_dns_hijacki.html

DNS hijacking isn’t new, but this seems to be an attack of unprecedented scale:

Researchers at Cisco’s Talos security division on Wednesday revealed that a hacker group it’s calling Sea Turtle carried out a broad campaign of espionage via DNS hijacking, hitting 40 different organizations. In the process, they went so far as to compromise multiple country-code top-level domains — the suffixes like .co.uk or .ru that end a foreign web address — putting all the traffic of every domain in multiple countries at risk.

The hackers’ victims include telecoms, internet service providers, and domain registrars responsible for implementing the domain name system. But the majority of the victims and the ultimate targets, Cisco believes, were a collection of mostly governmental organizations, including ministries of foreign affairs, intelligence agencies, military targets, and energy-related groups, all based in the Middle East and North Africa. By corrupting the internet’s directory system, hackers were able to silently use “man in the middle” attacks to intercept all internet data from email to web traffic sent to those victim organizations.

[…]

Cisco Talos said it couldn’t determine the nationality of the Sea Turtle hackers, and declined to name the specific targets of their spying operations. But it did provide a list of the countries where victims were located: Albania, Armenia, Cyprus, Egypt, Iraq, Jordan, Lebanon, Libya, Syria, Turkey, and the United Arab Emirates. Cisco’s Craig Williams confirmed that Armenia’s .am top-level domain was one of the “handful” that were compromised, but wouldn’t say which of the other countries’ top-level domains were similarly hijacked.

Another news article.

Real-Time Attacks Against Two-Factor Authentication

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/12/real-time_attac.html

Attackers are targeting two-factor authentication systems:

Attackers working on behalf of the Iranian government collected detailed information on targets and used that knowledge to write spear-phishing emails that were tailored to the targets’ level of operational security, researchers with security firm Certfa Lab said in a blog post. The emails contained a hidden image that alerted the attackers in real time when targets viewed the messages. When targets entered passwords into a fake Gmail or Yahoo security page, the attackers would almost simultaneously enter the credentials into a real login page. In the event targets’ accounts were protected by 2fa, the attackers redirected targets to a new page that requested a one-time password.

This isn’t new. I wrote about this exact attack in 2005 and 2009.

Security Vulnerabilities in Certificate Pinning

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/12/security_vulner_10.html

New research found that many banks offer certificate pinning as a security feature, but fail to authenticate the hostname. This leaves the systems open to man-in-the-middle attacks.

From the paper:

Abstract: Certificate verification is a crucial stage in the establishment of a TLS connection. A common security flaw in TLS implementations is the lack of certificate hostname verification but, in general, this is easy to detect. In security-sensitive applications, the usage of certificate pinning is on the rise. This paper shows that certificate pinning can (and often does) hide the lack of proper hostname verification, enabling MITM attacks. Dynamic (black-box) detection of this vulnerability would typically require the tester to own a high security certificate from the same issuer (and often same intermediate CA) as the one used by the app. We present Spinner, a new tool for black-box testing for this vulnerability at scale that does not require purchasing any certificates. By redirecting traffic to websites which use the relevant certificates and then analysing the (encrypted) network traffic we are able to determine whether the hostname check is correctly done, even in the presence of certificate pinning. We use Spinner to analyse 400 security-sensitive Android and iPhone apps. We found that 9 apps had this flaw, including two of the largest banks in the world: Bank of America and HSBC. We also found that TunnelBear, one of the most popular VPN apps was also vulnerable. These apps have a joint user base of tens of millions of users.

News article.

Man-in-the-Middle Attack against Electronic Car-Door Openers

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/11/man-in-the-midd_8.html

This is an interesting tactic, and there’s a video of it being used:

The theft took just one minute and the Mercedes car, stolen from the Elmdon area of Solihull on 24 September, has not been recovered.

In the footage, one of the men can be seen waving a box in front of the victim’s house.

The device receives a signal from the key inside and transmits it to the second box next to the car.

The car’s systems are then tricked into thinking the key is present and it unlocks, before the ignition can be started.

Cybercriminals Infiltrating E-Mail Networks to Divert Large Customer Payments

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/11/cybercriminals_.html

There’s a new criminal tactic involving hacking an e-mail account of a company that handles high-value transactions and diverting payments. Here it is in real estate:

The scam generally works like this: Hackers find an opening into a title company’s or realty agent’s email account, track upcoming home purchases scheduled for settlements — the pricier the better — then assume the identity of the title agency person handling the transaction.

Days or sometimes weeks before the settlement, the scammer poses as the title or escrow agent whose email accounts they’ve hijacked and instructs the home buyer to wire the funds needed to close — often hundreds of thousands of dollars, sometimes far more — to the criminals’ own bank accounts, not the title or escrow company’s legitimate accounts. The criminals then withdraw the money and vanish.

Here it is in fine art:

The fraud is relatively simple. Criminals hack into an art dealer’s email account and monitor incoming and outgoing correspondence. When the gallery sends a PDF invoice to a client via email following a sale, the conversation is hijacked. Posing as the gallery, hackers send a duplicate, fraudulent invoice from the same gallery email address, with an accompanying message instructing the client to disregard the first invoice and instead wire payment to the account listed in the fraudulent document.

Once money has been transferred to the criminals’ account, the hackers move the money to avoid detection and then disappear. The same technique is used to intercept payments made by galleries to their artists and others. Because the hackers gain access to the gallery’s email contacts, the scam can spread quickly, with fraudulent emails appearing to come from known sources.

I’m sure it’s happening in other industries as well, probably even with business-to-business commerce.

EDITED TO ADD (11/14): Brian Krebs wrote about this in 2014.

A Man-in-the-Middle Attack against a Password Reset System

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/07/a_man-in-the-mi.html

This is nice work: “The Password Reset MitM Attack,” by Nethanel Gelerntor, Senia Kalma, Bar Magnezi, and Hen Porcilan:

Abstract: We present the password reset MitM (PRMitM) attack and show how it can be used to take over user accounts. The PRMitM attack exploits the similarity of the registration and password reset processes to launch a man in the middle (MitM) attack at the application level. The attacker initiates a password reset process with a website and forwards every challenge to the victim who either wishes to register in the attacking site or to access a particular resource on it.

The attack has several variants, including exploitation of a password reset process that relies on the victim’s mobile phone, using either SMS or phone call. We evaluated the PRMitM attacks on Google and Facebook users in several experiments, and found that their password reset process is vulnerable to the PRMitM attack. Other websites and some popular mobile applications are vulnerable as well.

Although solutions seem trivial in some cases, our experiments show that the straightforward solutions are not as effective as expected. We designed and evaluated two secure password reset processes and evaluated them on users of Google and Facebook. Our results indicate a significant improvement in the security. Since millions of accounts are currently vulnerable to the PRMitM attack, we also present a list of recommendations for implementing and auditing the password reset process.

Password resets have long been a weak security link.

BoingBoing Post.

Separating the Paranoid from the Hacked

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/06/separating_the_.html

Sad story of someone whose computer became owned by a griefer:

The trouble began last year when he noticed strange things happening: files went missing from his computer; his Facebook picture was changed; and texts from his daughter didn’t reach him or arrived changed.

“Nobody believed me,” says Gary. “My wife and my brother thought I had lost my mind. They scheduled an appointment with a psychiatrist for me.”

But he built up a body of evidence and called in a professional cybersecurity firm. It found that his email addresses had been compromised, his phone records hacked and altered, and an entire virtual internet interface created.

“All my communications were going through a man-in-the-middle unauthorised server,” he explains.

It’s the “psychiatrist” quote that got me. I regularly get e-mails from people explaining in graphic detail how their whole lives have been hacked. Most of them are just paranoid. But a few of them are probably legitimate. And I have no way of telling them apart.

This problem isn’t going away. As computers permeate even more aspects of our lives, it’s going to get even more debilitating. And we don’t have any way, other than hiring a “professional cybersecurity firm,” of telling the paranoids from the victims.

Is WhatsApp Hacked?

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2016/10/is_whatsapp_hac.html

Forbes is reporting that the Israeli cyberweapons arms manufacturer Wintego has a man-in-the-middle exploit against WhatsApp.

It’s a weird story. I’m not sure how they do it, but something doesn’t sound right.

Another possibility is that CatchApp is malware thrust onto a device over Wi-Fi that specifically targets WhatsApp. But it’s almost certain the product cannot crack the latest standard of WhatsApp cryptography, said Matthew Green, a cryptography expert and assistant professor at the Johns Hopkins Information Security Institute. Green, who has been impressed by the quality of the Signal code, added: “They would have to defeat both the encryption to and from the server and the end-to-end Signal encryption. That does not seem feasible at all, even with a Wi-Fi access point.

“I would bet mundanely the password stuff is just plain phishing. You go to some site, it asks for your Google account, you type it in without looking closely at the address bar.

“But the WhatsApp stuff manifestly should not be vulnerable like that. Interesting.”

Neither WhatsApp nor the crypto whizz behind Signal, Moxie Marlinspike, were happy to comment unless more specific details were revealed about the tool’s capability. Either Wintego is embellishing what its real capability is, or it has a set of exploits that the rest of the world doesn’t yet know about.

Leaked Product Demo from RCS Labs

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2016/09/leaked_product_.html

We have leak from yet another cyberweapons arms manufacturer: the Italian company RCS Labs. Vice Motherboard reports on a surveillance video demo:

The video shows an RCS Lab employee performing a live demo of the company’s spyware to an unidentified man, including a tutorial on how to use the spyware’s control software to perform a man-in-the-middle attack and infect a target computer who wanted to visit a specific website.

RCS Lab’s spyware, called Mito3, allows agents to easily set up these kind of attacks just by applying a rule in the software settings. An agent can choose whatever site he or she wants to use as a vector, click on a dropdown menu and select “inject HTML” to force the malicious popup to appear, according to the video.

Mito3 allows customers to listen in on the target, intercept voice calls, text messages, video calls, social media activities, and chats, apparently both on computer and mobile platforms. It also allows police to track the target and geo-locate it thanks to the GPS. It even offers automatic transcription of the recordings, according to a confidential brochure obtained by Motherboard.

Slashdot thread

Credential Stealing as an Attack Vector

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2016/05/credential_stea.html

Traditional computer security concerns itself with vulnerabilities. We employ antivirus software to detect malware that exploits vulnerabilities. We have automatic patching systems to fix vulnerabilities. We debate whether the FBI should be permitted to introduce vulnerabilities in our software so it can get access to systems with a warrant. This is all important, but what’s missing is a recognition that software vulnerabilities aren’t the most common attack vector: credential stealing is.

The most common way hackers of all stripes, from criminals to hacktivists to foreign governments, break into networks is by stealing and using a valid credential. Basically, they steal passwords, set up man-in-the-middle attacks to piggy-back on legitimate logins, or engage in cleverer attacks to masquerade as authorized users. It’s a more effective avenue of attack in many ways: it doesn’t involve finding a zero-day or unpatched vulnerability, there’s less chance of discovery, and it gives the attacker more flexibility in technique.

Rob Joyce, the head of the NSA’s Tailored Access Operations (TAO) group — basically the country’s chief hacker — gave a rare public talk at a conference in January. In essence, he said that zero-day vulnerabilities are overrated, and credential stealing is how he gets into networks: “A lot of people think that nation states are running their operations on zero days, but it’s not that common. For big corporate networks, persistence and focus will get you in without a zero day; there are so many more vectors that are easier, less risky, and more productive.”

This is true for us, and it’s also true for those attacking us. It’s how the Chinese hackers breached the Office of Personnel Management in 2015. The 2014 criminal attack against Target Corporation started when hackers stole the login credentials of the company’s HVAC vendor. Iranian hackers stole US login credentials. And the hacktivist that broke into the cyber-arms manufacturer Hacking Team and published pretty much every proprietary document from that company used stolen credentials.

As Joyce said, stealing a valid credential and using it to access a network is easier, less risky, and ultimately more productive than using an existing vulnerability, even a zero-day.

Our notions of defense need to adapt to this change. First, organizations need to beef up their authentication systems. There are lots of tricks that help here: two-factor authentication, one-time passwords, physical tokens, smartphone-based authentication, and so on. None of these is foolproof, but they all make credential stealing harder.

Second, organizations need to invest in breach detection and — most importantly — incident response. Credential-stealing attacks tend to bypass traditional IT security software. But attacks are complex and multi-step. Being able to detect them in process, and to respond quickly and effectively enough to kick attackers out and restore security, is essential to resilient network security today.

Vulnerabilities are still critical. Fixing vulnerabilities is still vital for security, and introducing new vulnerabilities into existing systems is still a disaster. But strong authentication and robust incident response are also critical. And an organization that skimps on these will find itself unable to keep its networks secure.

This essay originally appeared on Xconomy.