Tag Archives: Malware

Interview with the Author of the 2000 Love Bug Virus

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/09/interview-with-the-author-of-the-2000-love-bug-virus.html

No real surprises, but we finally have the story.

The story he went on to tell is strikingly straightforward. De Guzman was poor, and internet access was expensive. He felt that getting online was almost akin to a human right (a view that was ahead of its time). Getting access required a password, so his solution was to steal the passwords from those who’d paid for them. Not that de Guzman regarded this as stealing: He argued that the password holder would get no less access as a result of having their password unknowingly “shared.” (Of course, his logic conveniently ignored the fact that the internet access provider would have to serve two people for the price of one.)

De Guzman came up with a solution: a password-stealing program. In hindsight, perhaps his guilt should have been obvious, because this was almost exactly the scheme he’d mapped out in a thesis proposal that had been rejected by his college the previous year.

North Korea ATM Hack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/09/north_korea_atm.html

The US Cybersecurity and Infrastructure Security Agency (CISA) published a long and technical alert describing a North Korea hacking scheme against ATMs in a bunch of countries worldwide:

This joint advisory is the result of analytic efforts among the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury (Treasury), the Federal Bureau of Investigation (FBI) and U.S. Cyber Command (USCYBERCOM). Working with U.S. government partners, CISA, Treasury, FBI, and USCYBERCOM identified malware and indicators of compromise (IOCs) used by the North Korean government in an automated teller machine (ATM) cash-out scheme­ — referred to by the U.S. Government as “FASTCash 2.0: North Korea’s BeagleBoyz Robbing Banks.”

The level of detail is impressive, as seems to be common in CISA’s alerts and analysis reports.

North Korea ATM Hack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/09/north_korea_atm.html

The US Cybersecurity and Infrastructure Security Agency (CISA) published a long and technical alert describing a North Korea hacking scheme against ATMs in a bunch of countries worldwide:

This joint advisory is the result of analytic efforts among the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury (Treasury), the Federal Bureau of Investigation (FBI) and U.S. Cyber Command (USCYBERCOM). Working with U.S. government partners, CISA, Treasury, FBI, and USCYBERCOM identified malware and indicators of compromise (IOCs) used by the North Korean government in an automated teller machine (ATM) cash-out scheme­ — referred to by the U.S. Government as “FASTCash 2.0: North Korea’s BeagleBoyz Robbing Banks.”

The level of detail is impressive, as seems to be common in CISA’s alerts and analysis reports.

Vaccine for Emotet Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/08/vaccine_for_emo.html

Interesting story of a vaccine for the Emotet malware:

Through trial and error and thanks to subsequent Emotet updates that refined how the new persistence mechanism worked, Quinn was able to put together a tiny PowerShell script that exploited the registry key mechanism to crash Emotet itself.

The script, cleverly named EmoCrash, effectively scanned a user’s computer and generated a correct — but malformed — Emotet registry key.

When Quinn tried to purposely infect a clean computer with Emotet, the malformed registry key triggered a buffer overflow in Emotet’s code and crashed the malware, effectively preventing users from getting infected.

When Quinn ran EmoCrash on computers already infected with Emotet, the script would replace the good registry key with the malformed one, and when Emotet would re-check the registry key, the malware would crash as well, preventing infected hosts from communicating with the Emotet command-and-control server.

[…]

The Binary Defense team quickly realized that news about this discovery needed to be kept under complete secrecy, to prevent the Emotet gang from fixing its code, but they understood EmoCrash also needed to make its way into the hands of companies across the world.

Compared to many of today’s major cybersecurity firms, all of which have decades of history behind them, Binary Defense was founded in 2014, and despite being one of the industry’s up-and-comers, it doesn’t yet have the influence and connections to get this done without news of its discovery leaking, either by accident or because of a jealous rival.

To get this done, Binary Defense worked with Team CYMRU, a company that has a decades-long history of organizing and participating in botnet takedowns.

Working behind the scenes, Team CYMRU made sure that EmoCrash made its way into the hands of national Computer Emergency Response Teams (CERTs), which then spread it to the companies in their respective jurisdictions.

According to James Shank, Chief Architect for Team CYMRU, the company has contacts with more than 125 national and regional CERT teams, and also manages a mailing list through which it distributes sensitive information to more than 6,000 members. Furthermore, Team CYMRU also runs a biweekly group dedicated to dealing with Emotet’s latest shenanigans.

This broad and well-orchestrated effort has helped EmoCrash make its way around the globe over the course of the past six months.

[…]

Either by accident or by figuring out there was something wrong in its persistence mechanism, the Emotet gang did, eventually, changed its entire persistence mechanism on Aug. 6 — exactly six months after Quinn made his initial discovery.

EmoCrash may not be useful to anyone anymore, but for six months, this tiny PowerShell script helped organizations stay ahead of malware operations — a truly rare sight in today’s cyber-security field.

Business Email Compromise (BEC) Criminal Ring

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/07/business_email_.html

A criminal group called Cosmic Lynx seems to be based in Russia:

Dubbed Cosmic Lynx, the group has carried out more than 200 BEC campaigns since July 2019, according to researchers from the email security firm Agari, particularly targeting senior executives at large organizations and corporations in 46 countries. Cosmic Lynx specializes in topical, tailored scams related to mergers and acquisitions; the group typically requests hundreds of thousands or even millions of dollars as part of its hustles.

[…]

For example, rather than use free accounts, Cosmic Lynx will register strategic domain names for each BEC campaign to create more convincing email accounts. And the group knows how to shield these domains so they’re harder to trace to the true owner. Cosmic Lynx also has a strong understanding of the email authentication protocol DMARC and does reconnaissance to assess its targets’ specific system DMARC policies to most effectively circumvent them.

Cosmic Lynx also drafts unusually clean and credible-looking messages to deceive targets. The group will find a company that is about to complete an acquisition and contact one of its top executives posing as the CEO of the organization being bought. This phony CEO will then involve “external legal counsel” to facilitate the necessary payments. This is where Cosmic Lynx adds a second persona to give the process an air of legitimacy, typically impersonating a real lawyer from a well-regarded law firm in the United Kingdom. The fake lawyer will email the same executive that the “CEO” wrote to, often in a new email thread, and share logistics about completing the transaction. Unlike most BEC campaigns, in which the messages often have grammatical mistakes or awkward wording, Cosmic Lynx messages are almost always clean.

ThiefQuest Ransomware for the Mac

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/07/thiefquest_rans.html

There’s a new ransomware for the Mac called ThiefQuest or EvilQuest. It’s hard to get infected:

For your Mac to become infected, you would need to torrent a compromised installer and then dismiss a series of warnings from Apple in order to run it. It’s a good reminder to get your software from trustworthy sources, like developers whose code is “signed” by Apple to prove its legitimacy, or from Apple’s App Store itself. But if you’re someone who already torrents programs and is used to ignoring Apple’s flags, ThiefQuest illustrates the risks of that approach.

But it’s nasty:

In addition to ransomware, ThiefQuest has a whole other set of spyware capabilities that allow it to exfiltrate files from an infected computer, search the system for passwords and cryptocurrency wallet data, and run a robust keylogger to grab passwords, credit card numbers, or other financial information as a user types it in. The spyware component also lurks persistently as a backdoor on infected devices, meaning it sticks around even after a computer reboots, and could be used as a launchpad for additional, or “second stage,” attacks. Given that ransomware is so rare on Macs to begin with, this one-two punch is especially noteworthy.

Android Apps Stealing Facebook Credentials

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/06/android_apps_st.html

Google has removed 25 Android apps from its store because they steal Facebook credentials:

Before being taken down, the 25 apps were collectively downloaded more than 2.34 million times.

The malicious apps were developed by the same threat group and despite offering different features, under the hood, all the apps worked the same.

According to a report from French cyber-security firm Evina shared with ZDNet today, the apps posed as step counters, image editors, video editors, wallpaper apps, flashlight applications, file managers, and mobile games.

The apps offered a legitimate functionality, but they also contained malicious code. Evina researchers say the apps contained code that detected what app a user recently opened and had in the phone’s foreground.

Nation-State Espionage Campaigns against Middle East Defense Contractors

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/06/nation-state_es.html

Report on espionage attacks using LinkedIn as a vector for malware, with details and screenshots. They talk about “several hints suggesting a possible link” to the Lazarus group (aka North Korea), but that’s by no means definite.

As part of the initial compromise phase, the Operation In(ter)ception attackers had created fake LinkedIn accounts posing as HR representatives of well-known companies in the aerospace and defense industries. In our investigation, we’ve seen profiles impersonating Collins Aerospace (formerly Rockwell Collins) and General Dynamics, both major US corporations in the field.

Detailed report.

AWS Shield Threat Landscape report is now available

Post Syndicated from Mario Pinho original https://aws.amazon.com/blogs/security/aws-shield-threat-landscape-report-now-available/

AWS Shield is a managed threat protection service that safeguards applications running on AWS against exploitation of application vulnerabilities, bad bots, and Distributed Denial of Service (DDoS) attacks. The AWS Shield Threat Landscape Report (TLR) provides you with a summary of threats detected by AWS Shield. This report is curated by the AWS Threat Response Team (TRT), who continually monitors and assesses the threat landscape to build protections on behalf of AWS customers. This includes rules and mitigations for services like AWS Managed Rules for AWS WAF and AWS Shield Advanced. You can use this information to expand your knowledge of external threats and improve the security of your applications running on AWS.

Here are some of our findings from the most recent report, which covers Q1 2020:

Volumetric Threat Analysis

AWS Shield detects network and web application-layer volumetric events that may indicate a DDoS attack, web content scraping, account takeover bots, or other unauthorized, non-human traffic. In Q1 2020, we observed significant increases in the frequency and volume of network volumetric threats, including a CLDAP reflection attack with a peak volume of 2.3 Tbps.

You can find a summary of the volumetric events detected in Q1 2020, compared to the same quarter in 2019, in the following table:

MetricSame Quarter, Prior Year (Q1 2019)
Most Recent Quarter (Q1 2020)
Change
Total number of events253,231310,954+23%
Largest bit rate (Tbps)0.82.3+188%
Largest packet rate (Mpps)260.1293.1+13%
Largest request rate (rps)1,000,414694,201-31%
Days of elevated threat*13+200%

Days of elevated threat indicates the number of days during which the volume or frequency of events was unusually high.

Malware Threat Analysis

AWS operates a threat intelligence platform that monitors Internet traffic and evaluates potentially suspicious interactions. We observed significant increases in the both the total number of events and the number of unique suspects, relative to the prior quarter. The most common interactions observed in Q1 2020 were Remote Code Execution (RCE) attempts on Apache Hadoop YARN applications, where the suspect attempts to exploit the API of a Hadoop cluster’s resource management system and execute code, without authorization. In March 2020, these interactions accounted for 31% of all events detected by the threat intelligence platform.

You can find a summary of the volumetric events detected in Q1 2020, compared to the prior quarter, in the following table:

MetricPrior Quarter
(Q4 2019)
Most Recent Quarter
(Q1 2020)
Change
Total number of events (billion)0.71.1+57%
Unique suspects (million)1.21.6+33%

 

For more information about the threats detected by AWS Shield in Q1 2020 and steps that you can take to protect your applications running on AWS, download the AWS Shield Threat Landscape Report.

If you have feedback about this post, submit comments in the Comments section below. If you have questions about this blog post, start a new thread on the AWS Shield forum or contact AWS Support.

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Author

Mario Pinho

Mario Pinho is a Security Engineer at AWS. He has a background in network engineering and consulting, and feels at his best when breaking apart complex topics and processes into its simpler components. In his free time he pretends to be an artist by playing piano and doing landscape photography.

Ramsey Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/05/ramsey_malware.html

A new malware, called Ramsey, can jump air gaps:

ESET said they’ve been able to track down three different versions of the Ramsay malware, one compiled in September 2019 (Ramsay v1), and two others in early and late March 2020 (Ramsay v2.a and v2.b).

Each version was different and infected victims through different methods, but at its core, the malware’s primary role was to scan an infected computer, and gather Word, PDF, and ZIP documents in a hidden storage folder, ready to be exfiltrated at a later date.

Other versions also included a spreader module that appended copies of the Ramsay malware to all PE (portable executable) files found on removable drives and network shares. This is believed to be the mechanism the malware was employing to jump the air gap and reach isolated networks, as users would most likely moved the infected executables between the company’s different network layers, and eventually end up on an isolated system.

ESET says that during its research, it was not able to positively identify Ramsay’s exfiltration module, or determine how the Ramsay operators retrieved data from air-gapped systems.

Honestly, I can’t think of any threat actor that wants this kind of feature other than governments:

The researcher has not made a formal attribution as who might be behind Ramsay. However, Sanmillan said that the malware contained a large number of shared artifacts with Retro, a malware strain previously developed by DarkHotel, a hacker group that many believe to operate in the interests of the South Korean government.

Seems likely.

Details.

US Government Exposes North Korean Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/05/us_government_e.html

US Cyber Command has uploaded North Korean malware samples to the VirusTotal aggregation repository, adding to the malware samples it uploaded in February.

The first of the new malware variants, COPPERHEDGE, is described as a Remote Access Tool (RAT) “used by advanced persistent threat (APT) cyber actors in the targeting of cryptocurrency exchanges and related entities.”

This RAT is known for its capability to help the threat actors perform system reconnaissance, run arbitrary commands on compromised systems, and exfiltrate stolen data.

TAINTEDSCRIBE is a trojan that acts as a full-featured beaconing implant with command modules and designed to disguise as Microsoft’s Narrator.

The trojan “downloads its command execution module from a command and control (C2) server and then has the capability to download, upload, delete, and execute files; enable Windows CLI access; create and terminate processes; and perform target system enumeration.”

Last but not least, PEBBLEDASH is yet another North Korean trojan acting like a full-featured beaconing implant and used by North Korean-backed hacking groups “to download, upload, delete, and execute files; enable Windows CLI access; create and terminate processes; and perform target system enumeration.”

It’s interesting to see the US government take a more aggressive stance on foreign malware. Making samples public, so all the antivirus companies can add them to their scanning systems, is a big deal — and probably required some complicated declassification maneuvering.

Me, I like reading the codenames.

Lots more on the US-CERT website.

iOS XML Bug

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/05/ios_xml_bug.html

This is a good explanation of an iOS bug that allowed someone to break out of the application sandbox. A summary:

What a crazy bug, and Siguza’s explanation is very cogent. Basically, it comes down to this:

  • XML is terrible.
  • iOS uses XML for Plists, and Plists are used everywhere in iOS (and MacOS).
  • iOS’s sandboxing system depends upon three different XML parsers, which interpret slightly invalid XML input in slightly different ways.

So Siguza’s exploit ­– which granted an app full access to the entire file system, and more ­- uses malformed XML comments constructed in a way that one of iOS’s XML parsers sees its declaration of entitlements one way, and another XML parser sees it another way. The XML parser used to check whether an application should be allowed to launch doesn’t see the fishy entitlements because it thinks they’re inside a comment. The XML parser used to determine whether an already running application has permission to do things that require entitlements sees the fishy entitlements and grants permission.

This is fixed in the new iOS release, 13.5 beta 3.

Comment:

Implementing 4 different parsers is just asking for trouble, and the “fix” is of the crappiest sort, bolting on more crap to check they’re doing the right thing in this single case. None of this is encouraging.

More commentary. Hacker News thread.

Malware in Google Apps

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/05/malware_in_goog_1.html

Interesting story of malware hidden in Google Apps. This particular campaign is tied to the government of Vietnam.

At a remote virtual version of its annual Security Analyst Summit, researchers from the Russian security firm Kaspersky today plan to present research about a hacking campaign they call PhantomLance, in which spies hid malware in the Play Store to target users in Vietnam, Bangladesh, Indonesia, and India. Unlike most of the shady apps found in Play Store malware, Kaspersky’s researchers say, PhantomLance’s hackers apparently smuggled in data-stealing apps with the aim of infecting only some hundreds of users; the spy campaign likely sent links to the malicious apps to those targets via phishing emails. “In this case, the attackers used Google Play as a trusted source,” says Kaspersky researcher Alexey Firsh. “You can deliver a link to this app, and the victim will trust it because it’s Google Play.”

[…]

The first hints of PhantomLance’s campaign focusing on Google Play came to light in July of last year. That’s when Russian security firm Dr. Web found a sample of spyware in Google’s app store that impersonated a downloader of graphic design software but in fact had the capability to steal contacts, call logs, and text messages from Android phones. Kaspersky’s researchers found a similar spyware app, impersonating a browser cache-cleaning tool called Browser Turbo, still active in Google Play in November of that year. (Google removed both malicious apps from Google Play after they were reported.) While the espionage capabilities of those apps was fairly basic, Firsh says that they both could have expanded. “What’s important is the ability to download new malicious payloads,” he says. “It could extend its features significantly.”

Kaspersky went on to find tens of other, similar spyware apps dating back to 2015 that Google had already removed from its Play Store, but which were still visible in archived mirrors of the app repository. Those apps appeared to have a Vietnamese focus, offering tools for finding nearby churches in Vietnam and Vietnamese-language news. In every case, Firsh says, the hackers had created a new account and even Github repositories for spoofed developers to make the apps appear legitimate and hide their tracks.

Emotet Malware Causes Physical Damage

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/04/emotat_malware_.html

Microsoft is reporting that an Emotet malware infection shut down a network by causing computers to overheat and then crash.

The Emotet payload was delivered and executed on the systems of Fabrikam — a fake name Microsoft gave the victim in their case study — five days after the employee’s user credentials were exfiltrated to the attacker’s command and control (C&C) server.

Before this, the threat actors used the stolen credentials to deliver phishing emails to other Fabrikam employees, as well as to their external contacts, with more and more systems getting infected and downloading additional malware payloads.

The malware further spread through the network without raising any red flags by stealing admin account credentials authenticating itself on new systems, later used as stepping stones to compromise other devices.

Within 8 days since that first booby-trapped attachment was opened, Fabrikam’s entire network was brought to its knees despite the IT department’s efforts, with PCs overheating, freezing, and rebooting because of blue screens, and Internet connections slowing down to a crawl because of Emotet devouring all the bandwidth.

The infection mechanism was one employee opening a malicious attachment to a phishing email. I can’t find any information on what kind of attachment.

Deep Learning to Find Malicious Email Attachments

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/02/deep_learning_t.html

Google presented its system of using deep-learning techniques to identify malicious email attachments:

At the RSA security conference in San Francisco on Tuesday, Google’s security and anti-abuse research lead Elie Bursztein will present findings on how the new deep-learning scanner for documents is faring against the 300 billion attachments it has to process each week. It’s challenging to tell the difference between legitimate documents in all their infinite variations and those that have specifically been manipulated to conceal something dangerous. Google says that 63 percent of the malicious documents it blocks each day are different than the ones its systems flagged the day before. But this is exactly the type of pattern-recognition problem where deep learning can be helpful.

[…]

The document analyzer looks for common red flags, probes files if they have components that may have been purposefully obfuscated, and does other checks like examining macros­ — the tool in Microsoft Word documents that chains commands together in a series and is often used in attacks. The volume of malicious documents that attackers send out varies widely day to day. Bursztein says that since its deployment, the document scanner has been particularly good at flagging suspicious documents sent in bursts by malicious botnets or through other mass distribution methods. He was also surprised to discover how effective the scanner is at analyzing Microsoft Excel documents, a complicated file format that can be difficult to assess.

This is the sort of thing that’s pretty well optimized for machine-learning techniques.

New Ransomware Targets Industrial Control Systems

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/02/new_ransomware_.html

EKANS is a new ransomware that targets industrial control systems:

But EKANS also uses another trick to ratchet up the pain: It’s designed to terminate 64 different software processes on victim computers, including many that are specific to industrial control systems. That allows it to then encrypt the data that those control system programs interact with. While crude compared to other malware purpose-built for industrial sabotage, that targeting can nonetheless break the software used to monitor infrastructure, like an oil firm’s pipelines or a factory’s robots. That could have potentially dangerous consequences, like preventing staff from remotely monitoring or controlling the equipment’s operation.

EKANS is actually the second ransomware to hit industrial control systems. According to Dragos, another ransomware strain known as Megacortex that first appeared last spring included all of the same industrial control system process-killing features, and may in fact be a predecessor to EKANS developed by the same hackers. But because Megacortex also terminated hundreds of other processes, its industrial-control-system targeted features went largely overlooked.

Speculation is that this is criminal in origin, and not the work of a government.

It’s also the first malware that is named after a Pokémon character.

Technical Report of the Bezos Phone Hack

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

Motherboard obtained and published the technical report on the hack of Jeff Bezos’s phone, which is being attributed to Saudi Arabia, specifically to Crown Prince Mohammed bin Salman.

…investigators set up a secure lab to examine the phone and its artifacts and spent two days poring over the device but were unable to find any malware on it. Instead, they only found a suspicious video file sent to Bezos on May 1, 2018 that “appears to be an Arabic language promotional film about telecommunications.”

That file shows an image of the Saudi Arabian flag and Swedish flags and arrived with an encrypted downloader. Because the downloader was encrypted this delayed or further prevented “study of the code delivered along with the video.”

Investigators determined the video or downloader were suspicious only because Bezos’ phone subsequently began transmitting large amounts of data. “[W]ithin hours of the encrypted downloader being received, a massive and unauthorized exfiltration of data from Bezos’ phone began, continuing and escalating for months thereafter,” the report states.

“The amount of data being transmitted out of Bezos’ phone changed dramatically after receiving the WhatsApp video file and never returned to baseline. Following execution of the encrypted downloader sent from MBS’ account, egress on the device immediately jumped by approximately 29,000 percent,” it notes. “Forensic artifacts show that in the six (6) months prior to receiving the WhatsApp video, Bezos’ phone had an average of 430KB of egress per day, fairly typical of an iPhone. Within hours of the WhatsApp video, egress jumped to 126MB. The phone maintained an unusually high average of 101MB of egress data per day for months thereafter, including many massive and highly atypical spikes of egress data.”

The Motherboard article also quotes forensic experts on the report:

A mobile forensic expert told Motherboard that the investigation as depicted in the report is significantly incomplete and would only have provided the investigators with about 50 percent of what they needed, especially if this is a nation-state attack. She says the iTunes backup and other extractions they did would get them only messages, photo files, contacts and other files that the user is interested in saving from their applications, but not the core files.

“They would need to use a tool like Graykey or Cellebrite Premium or do a jailbreak to get a look at the full file system. That’s where that state-sponsored malware is going to be found. Good state-sponsored malware should never show up in a backup,” said Sarah Edwards, an author and teacher of mobile forensics for the SANS Institute.

“The full file system is getting into the device and getting every single file on there­ — the whole operating system, the application data, the databases that will not be backed up. So really the in-depth analysis should be done on that full file system, for this level of investigation anyway. I would have insisted on that right from the start.”

The investigators do note on the last page of their report that they need to jailbreak Bezos’s phone to examine the root file system. Edwards said this would indeed get them everything they would need to search for persistent spyware like the kind created and sold by the NSO Group. But the report doesn’t indicate if that did get done.

ToTok Is an Emirati Spying Tool

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2019/12/totok_is_an_emi.html

The smartphone messaging app ToTok is actually an Emirati spying tool:

But the service, ToTok, is actually a spying tool, according to American officials familiar with a classified intelligence assessment and a New York Times investigation into the app and its developers. It is used by the government of the United Arab Emirates to try to track every conversation, movement, relationship, appointment, sound and image of those who install it on their phones.

ToTok, introduced only months ago, was downloaded millions of times from the Apple and Google app stores by users throughout the Middle East, Europe, Asia, Africa and North America. While the majority of its users are in the Emirates, ToTok surged to become one of the most downloaded social apps in the United States last week, according to app rankings and App Annie, a research firm.

Apple and Google have removed it from their app stores. If you have it on your phone, delete it now.