Entries Tagged "backdoors"

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Intentional Flaw in GPRS Encryption Algorithm GEA-1

General Packet Radio Service (GPRS) is a mobile data standard that was widely used in the early 2000s. The first encryption algorithm for that standard was GEA-1, a stream cipher built on three linear-feedback shift registers and a non-linear combining function. Although the algorithm has a 64-bit key, the effective key length is only 40 bits, due to “an exceptional interaction of the deployed LFSRs and the key initialization, which is highly unlikely to occur by chance.”

GEA-1 was designed by the European Telecommunications Standards Institute in 1998. ETSI was—and maybe still is—under the auspices of SOGIS: the Senior Officials Group, Information Systems Security. That’s basically the intelligence agencies of the EU countries.

Details are in the paper: “Cryptanalysis of the GPRS Encryption Algorithms GEA-1 and GEA-2.” GEA-2 does not have the same flaw, although the researchers found a practical attack with enough keystream.

Hacker News thread.

EDITED TO ADD (6/18): News article.

Posted on June 17, 2021 at 1:51 PM • View Comments

FBI/AFP-Run Encrypted Phone

For three years, the Federal Bureau of Investigation and the Australian Federal Police owned and operated a commercial encrypted phone app, called AN0M, that was used by organized crime around the world. Of course, the police were able to read everything—I don’t even know if this qualifies as a backdoor. This week, the world’s police organizations announced 800 arrests based on text messages sent over the app. We’ve seen law enforcement take over encrypted apps before: for example, EncroChat. This operation, code-named Trojan Shield, is the first time law enforcement managed an app from the beginning.

If there is any moral to this, it’s one that all of my blog readers should already know: trust is essential to security. And the number of people you need to trust is larger than you might originally think. For an app to be secure, you need to trust the hardware, the operating system, the software, the update mechanism, the login mechanism, and on and on and on. If one of those is untrustworthy, the whole system is insecure.

It’s the same reason blockchain-based currencies are so insecure, even if the cryptography is sound.

Posted on June 11, 2021 at 6:32 AM • View Comments

Bizarro Banking Trojan

Bizarro is a new banking trojan that is stealing financial information and crypto wallets.

…the program can be delivered in a couple of ways­—either via malicious links contained within spam emails, or through a trojanized app. Using these sneaky methods, trojan operators will implant the malware onto a target device, where it will install a sophisticated backdoor that “contains more than 100 commands and allows the attackers to steal online banking account credentials,” the researchers write.

The backdoor has numerous commands built in to allow manipulation of a targeted individual, including keystroke loggers that allow for harvesting of personal login information. In some instances, the malware can allow criminals to commandeer a victim’s crypto wallet, too.

Research report.

Posted on May 20, 2021 at 9:13 AM • View Comments

Backdoor Found in Codecov Bash Uploader

Developers have discovered a backdoor in the Codecov bash uploader. It’s been there for four months. We don’t know who put it there.

Codecov said the breach allowed the attackers to export information stored in its users’ continuous integration (CI) environments. This information was then sent to a third-party server outside of Codecov’s infrastructure,” the company warned.

Codecov’s Bash Uploader is also used in several uploaders—Codecov-actions uploader for Github, the Codecov CircleCl Orb, and the Codecov Bitrise Step—and the company says these uploaders were also impacted by the breach.

According to Codecov, the altered version of the Bash Uploader script could potentially affect:

  • Any credentials, tokens, or keys that our customers were passing through their CI runner that would be accessible when the Bash Uploader script was executed.
  • Any services, datastores, and application code that could be accessed with these credentials, tokens, or keys.
  • The git remote information (URL of the origin repository) of repositories using the Bash Uploaders to upload coverage to Codecov in CI.

Add this to the long list of recent supply-chain attacks.

Posted on April 21, 2021 at 11:12 AM • View Comments

Backdoor Added—But Found—in PHP

Unknown hackers attempted to add a backdoor to the PHP source code. It was two malicious commits, with the subject “fix typo” and the names of known PHP developers and maintainers. They were discovered and removed before being pushed out to any users. But since 79% of the Internet’s websites use PHP, it’s scary.

Developers have moved PHP to GitHub, which has better authentication. Hopefully it will be enough—PHP is a juicy target.

Posted on April 9, 2021 at 8:54 AM • View Comments

Chinese Supply-Chain Attack on Computer Systems

Bloomberg News has a major story about the Chinese hacking computer motherboards made by Supermicro, Levono, and others. It’s been going on since at least 2008. The US government has known about it for almost as long, and has tried to keep the attack secret:

China’s exploitation of products made by Supermicro, as the U.S. company is known, has been under federal scrutiny for much of the past decade, according to 14 former law enforcement and intelligence officials familiar with the matter. That included an FBI counterintelligence investigation that began around 2012, when agents started monitoring the communications of a small group of Supermicro workers, using warrants obtained under the Foreign Intelligence Surveillance Act, or FISA, according to five of the officials.

There’s lots of detail in the article, and I recommend that you read it through.

This is a follow on, with a lot more detail, to a story Bloomberg reported on in fall 2018. I didn’t believe the story back then, writing:

I don’t think it’s real. Yes, it’s plausible. But first of all, if someone actually surreptitiously put malicious chips onto motherboards en masse, we would have seen a photo of the alleged chip already. And second, there are easier, more effective, and less obvious ways of adding backdoors to networking equipment.

I seem to have been wrong. From the current Bloomberg story:

Mike Quinn, a cybersecurity executive who served in senior roles at Cisco Systems Inc. and Microsoft Corp., said he was briefed about added chips on Supermicro motherboards by officials from the U.S. Air Force. Quinn was working for a company that was a potential bidder for Air Force contracts, and the officials wanted to ensure that any work would not include Supermicro equipment, he said. Bloomberg agreed not to specify when Quinn received the briefing or identify the company he was working for at the time.

“This wasn’t a case of a guy stealing a board and soldering a chip on in his hotel room; it was architected onto the final device,” Quinn said, recalling details provided by Air Force officials. The chip “was blended into the trace on a multilayered board,” he said.

“The attackers knew how that board was designed so it would pass” quality assurance tests, Quinn said.

Supply-chain attacks are the flavor of the moment, it seems. But they’re serious, and very hard to defend against in our deeply international IT industry. (I have repeatedly called this an “insurmountable problem.”) Here’s me in 2018:

Supply-chain security is an incredibly complex problem. US-only design and manufacturing isn’t an option; the tech world is far too internationally interdependent for that. We can’t trust anyone, yet we have no choice but to trust everyone. Our phones, computers, software and cloud systems are touched by citizens of dozens of different countries, any one of whom could subvert them at the demand of their government.

We need some fundamental security research here. I wrote this in 2019:

The other solution is to build a secure system, even though any of its parts can be subverted. This is what the former Deputy Director of National Intelligence Sue Gordon meant in April when she said about 5G, “You have to presume a dirty network.” Or more precisely, can we solve this by building trustworthy systems out of untrustworthy parts?

It sounds ridiculous on its face, but the Internet itself was a solution to a similar problem: a reliable network built out of unreliable parts. This was the result of decades of research. That research continues today, and it’s how we can have highly resilient distributed systems like Google’s network even though none of the individual components are particularly good. It’s also the philosophy behind much of the cybersecurity industry today: systems watching one another, looking for vulnerabilities and signs of attack.

It seems that supply-chain attacks are constantly in the news right now. That’s good. They’ve been a serious problem for a long time, and we need to take the threat seriously. For further reading, I strongly recommend this Atlantic Council report from last summer: “Breaking trust: Shades of crisis across an insecure software supply chain.“

Posted on February 13, 2021 at 9:41 AM • View Comments

Another SolarWinds Orion Hack

At the same time the Russians were using a backdoored SolarWinds update to attack networks worldwide, another threat actor—believed to be Chinese in origin—was using an already existing vulnerability in Orion to penetrate networks:

Two people briefed on the case said FBI investigators recently found that the National Finance Center, a federal payroll agency inside the U.S. Department of Agriculture, was among the affected organizations, raising fears that data on thousands of government employees may have been compromised.

[…]

Reuters was not able to establish how many organizations were compromised by the suspected Chinese operation. The sources, who spoke on condition of anonymity to discuss ongoing investigations, said the attackers used computer infrastructure and hacking tools previously deployed by state-backed Chinese cyberspies.

[…]

While the alleged Russian hackers penetrated deep into SolarWinds network and hid a “back door” in Orion software updates which were then sent to customers, the suspected Chinese group exploited a separate bug in Orion’s code to help spread across networks they had already compromised, the sources said.

Two takeaways: One, we are learning about a lot of supply-chain attacks right now. Two, SolarWinds’ terrible security is the result of a conscious business decision to reduce costs in the name of short-term profits. Economist Matt Stoller writes about this:

These private equity-owned software firms torture professionals with bad user experiences and shitty customer support in everything from yoga studio software to car dealer IT to the nightmarish ‘core’ software that runs small banks and credit unions, as close as one gets to automating Office Space. But they also degrade product quality by firing or disrespecting good workers, under-investing in good security practices, or sending work abroad and paying badly, meaning their products are more prone to espionage. In other words, the same sloppy and corrupt practices that allowed this massive cybersecurity hack made Bravo a billionaire. In a sense, this hack, and many more like it, will continue to happen, as long as men like Bravo get rich creating security vulnerabilities for bad actors to exploit.

SolarWinds increased its profits by increasing its cybersecurity risk, and then transferred that risk to its customers without their knowledge or consent.

Posted on February 4, 2021 at 6:11 AM • View Comments

Police Have Disrupted the Emotet Botnet

A coordinated effort has captured the command-and-control servers of the Emotet botnet:

Emotet establishes a backdoor onto Windows computer systems via automated phishing emails that distribute Word documents compromised with malware. Subjects of emails and documents in Emotet campaigns are regularly altered to provide the best chance of luring victims into opening emails and installing malware—regular themes include invoices, shipping notices and information about COVID-19.

Those behind the Emotet lease their army of infected machines out to other cyber criminals as a gateway for additional malware attacks, including remote access tools (RATs) and ransomware.

[…]

A week of action by law enforcement agencies around the world gained control of Emotet’s infrastructure of hundreds of servers around the world and disrupted it from the inside.

Machines infected by Emotet are now directed to infrastructure controlled by law enforcement, meaning cyber criminals can no longer exploit machines compromised and the malware can no longer spread to new targets, something which will cause significant disruption to cyber-criminal operations.

[…]

The Emotet takedown is the result of over two years of coordinated work by law enforcement operations around the world, including the Dutch National Police, Germany’s Federal Crime Police, France’s National Police, the Lithuanian Criminal Police Bureau, the Royal Canadian Mounted Police, the US Federal Bureau of Investigation, the UK’s National Crime Agency, and the National Police of Ukraine.

EDITED TO ADD (2/11): Follow-on article.

Posted on January 28, 2021 at 6:02 AM • View Comments

SVR Attacks on Microsoft 365

FireEye is reporting the current known tactics that the SVR used to compromise Microsoft 365 cloud data as part of its SolarWinds operation:

Mandiant has observed UNC2452 and other threat actors moving laterally to the Microsoft 365 cloud using a combination of four primary techniques:

  • Steal the Active Directory Federation Services (AD FS) token-signing certificate and use it to forge tokens for arbitrary users (sometimes described as Golden SAML). This would allow the attacker to authenticate into a federated resource provider (such as Microsoft 365) as any user, without the need for that user’s password or their corresponding multi-factor authentication (MFA) mechanism.
  • Modify or add trusted domains in Azure AD to add a new federated Identity Provider (IdP) that the attacker controls. This would allow the attacker to forge tokens for arbitrary users and has been described as an Azure AD backdoor.
  • Compromise the credentials of on-premises user accounts that are synchronized to Microsoft 365 that have high privileged directory roles, such as Global Administrator or Application Administrator.
  • Backdoor an existing Microsoft 365 application by adding a new application or service principal credential in order to use the legitimate permissions assigned to the application, such as the ability to read email, send email as an arbitrary user, access user calendars, etc.

Lots of details here, including information on remediation and hardening.

The more we learn about the this operation, the more sophisticated it becomes.

In related news, MalwareBytes was also targeted.

Posted on January 21, 2021 at 6:31 AM • View Comments

Injecting a Backdoor into SolarWinds Orion

Crowdstrike is reporting on a sophisticated piece of malware that was able to inject malware into the SolarWinds build process:

Key Points

  • SUNSPOT is StellarParticle’s malware used to insert the SUNBURST backdoor into software builds of the SolarWinds Orion IT management product.
  • SUNSPOT monitors running processes for those involved in compilation of the Orion product and replaces one of the source files to include the SUNBURST backdoor code.
  • Several safeguards were added to SUNSPOT to avoid the Orion builds from failing, potentially alerting developers to the adversary’s presence.

Analysis of a SolarWinds software build server provided insights into how the process was hijacked by StellarParticle in order to insert SUNBURST into the update packages. The design of SUNSPOT suggests StellarParticle developers invested a lot of effort to ensure the code was properly inserted and remained undetected, and prioritized operational security to avoid revealing their presence in the build environment to SolarWinds developers.

This, of course, reminds many of us of Ken Thompson’s thought experiment from his 1984 Turing Award lecture, “Reflections on Trusting Trust.” In that talk, he suggested that a malicious C compiler might add a backdoor into programs it compiles.

The moral is obvious. You can’t trust code that you did not totally create yourself. (Especially code from companies that employ people like me.) No amount of source-level verification or scrutiny will protect you from using untrusted code. In demonstrating the possibility of this kind of attack, I picked on the C compiler. I could have picked on any program-handling program such as an assembler, a loader, or even hardware microcode. As the level of program gets lower, these bugs will be harder and harder to detect. A well-installed microcode bug will be almost impossible to detect.

That’s all still true today.

Posted on January 19, 2021 at 6:16 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.