backdoors

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Crooks plant backdoor in software used by courtrooms around the world

audio/video, backdoors, Biz & IT, Cybersecurity, Security, supply chain attacks / /

DISORDER IN THE COURT —

It’s unclear how the malicious version of JAVS Viewer came to be.

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Crooks plant backdoor in software used by courtrooms around the world

JAVS

A software maker serving more than 10,000 courtrooms throughout the world hosted an application update containing a hidden backdoor that maintained persistent communication with a malicious website, researchers reported Thursday, in the latest episode of a supply-chain attack.

The software, known as the JAVS Viewer 8, is a component of the JAVS Suite 8, an application package courtrooms use to record, play back, and manage audio and video from proceedings. Its maker, Louisville, Kentucky-based Justice AV Solutions, says its products are used in more than 10,000 courtrooms throughout the US and 11 other countries. The company has been in business for 35 years.

JAVS Viewer users at high risk

Researchers from security firm Rapid7 reported that a version of the JAVS Viewer 8 available for download on javs.com contained a backdoor that gave an unknown threat actor persistent access to infected devices. The malicious download, planted inside an executable file that installs the JAVS Viewer version 8.3.7, was available no later than April 1, when a post on X (formerly Twitter) reported it. It’s unclear when the backdoored version was removed from the company’s download page. JAVS representatives didn’t immediately respond to questions sent by email.

“Users who have version 8.3.7 of the JAVS Viewer executable installed are at high risk and should take immediate action,” Rapid7 researchers Ipek Solak, Thomas Elkins, Evan McCann, Matthew Smith, Jake McMahon, Tyler McGraw, Ryan Emmons, Stephen Fewer, and John Fenninger wrote. “This version contains a backdoored installer that allows attackers to gain full control of affected systems.”

The installer file was titled JAVS Viewer Setup 8.3.7.250-1.exe. When executed, it copied the binary file fffmpeg.exe to the file path C:Program Files (x86)JAVSViewer 8. To bypass security warnings, the installer was digitally signed, but with a signature issued to an entity called “Vanguard Tech Limited” rather than to “Justice AV Solutions Inc.,” the signing entity used to authenticate legitimate JAVS software.

fffmpeg.exe, in turn, used Windows Sockets and WinHTTP to establish communications with a command-and-control server. Once successfully connected, fffmpeg.exe sent the server passwords harvested from browsers and data about the compromised host, including hostname, operating system details, processor architecture, program working directory, and the user name.

The researchers said fffmpeg.exe also downloaded the file chrome_installer.exe from the IP address 45.120.177.178. chrome_installer.exe went on to execute a binary and several Python scripts that were responsible for stealing the passwords saved in browsers. fffmpeg.exe is associated with a known malware family called GateDoor/Rustdoor. The exe file was already flagged by 30 endpoint protection engines.

A screenshot from VirusTotal showing detections from 30 endpoint protection engines.

Enlarge / A screenshot from VirusTotal showing detections from 30 endpoint protection engines.

Rapid7

The number of detections had grown to 38 at the time this post went live.

The researchers warned that the process of disinfecting infected devices will require care. They wrote:

To remediate this issue, affected users should:

  • Reimage any endpoints where JAVS Viewer 8.3.7 was installed. Simply uninstalling the software is insufficient, as attackers may have implanted additional backdoors or malware. Re-imaging provides a clean slate.
  • Reset credentials for any accounts that were logged into affected endpoints. This includes local accounts on the endpoint itself as well as any remote accounts accessed during the period when JAVS Viewer 8.3.7 was installed. Attackers may have stolen credentials from compromised systems.
  • Reset credentials used in web browsers on affected endpoints. Browser sessions may have been hijacked to steal cookies, stored passwords, or other sensitive information.
  • Install the latest version of JAVS Viewer (8.3.8 or higher) after re-imaging affected systems. The new version does not contain the backdoor present in 8.3.7.

Completely re-imaging affected endpoints and resetting associated credentials is critical to ensure attackers have not persisted through backdoors or stolen credentials. All organizations running JAVS Viewer 8.3.7 should take these steps immediately to address the compromise.

The Rapid7 post included a statement from JAVS that confirmed that the installer for version 8.3.7 of the JAVS viewer was malicious.

“We pulled all versions of Viewer 8.3.7 from the JAVS website, reset all passwords, and conducted a full internal audit of all JAVS systems,” the statement read. “We confirmed all currently available files on the JAVS.com website are genuine and malware-free. We further verified that no JAVS Source code, certificates, systems, or other software releases were compromised in this incident.”

The statement didn’t explain how the installer became available for download on its site. It also didn’t say if the company retained an outside firm to investigate.

The incident is the latest example of a supply-chain attack, a technique that tampers with a legitimate service or piece of software with the aim of infecting all downstream users. These sorts of attacks are usually carried out by first hacking the provider of the service or software. There’s no sure way to prevent falling victim to supply-chain attacks, but one potentially useful measure is to vet a file using VirusTotal before executing it. That advice would have served JAVS users well.

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Hackers infect users of antivirus service that delivered updates over HTTP

antivirus, backdoors, Biz & IT, Encryption, HTTP, HTTPS, man in the middle, Security / /

GOT HTTPS? —

eScan AV updates were delivered over HTTP for five years.

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Hackers infect users of antivirus service that delivered updates over HTTP

Getty Images

Hackers abused an antivirus service for five years in order to infect end users with malware. The attack worked because the service delivered updates over HTTP, a protocol vulnerable to attacks that corrupt or tamper with data as it travels over the Internet.

The unknown hackers, who may have ties to the North Korean government, pulled off this feat by performing a man-in-the-middle (MiitM) attack that replaced the genuine update with a file that installed an advanced backdoor instead, said researchers from security firm Avast today.

eScan, an AV service headquartered in India, has delivered updates over HTTP since at least 2019, Avast researchers reported. This protocol presented a valuable opportunity for installing the malware, which is tracked in security circles under the name GuptiMiner.

“This sophisticated operation has been performing MitM attacks targeting an update mechanism of the eScan antivirus vendor,” Avast researchers Jan Rubín and Milánek wrote. “We disclosed the security vulnerability to both eScan and the India CERT and received confirmation on 2023-07-31 from eScan that the issue was fixed and successfully resolved.”

Complex infection chain

The complex infection chain started when eScan applications checked in with the eScan update system. The threat actors then performed a MitM attack that allowed them to intercept the package sent by the update server and replace it with a corrupted one that contained code to install GuptiMiner. The Avast researchers still don’t know precisely how the attackers were able to perform the interception. They suspect targeted networks may already have been compromised somehow to route traffic to a malicious intermediary.

To lower the chances of detection, the infection file used DLL hijacking, a technique that replaces legitimate dynamic link library files used by most Microsoft apps with maliciously crafted ones that use the same file name. For added stealth, the infection chain also relied on a custom domain name system (DNS)  server that allowed it to use legitimate domain names when connecting to attacker-controlled channels.

Last year, the attackers abandoned the DNS technique and replaced it with another obfuscation technique known as IP address masking. This involved the following steps:

  1. Obtain an IP address of a hardcoded server name registered to the attacker by standard use of the gethostbyname API function
  2. For that server, two IP addresses are returned—the first is an IP address which is a masked address, and the second one denotes an available payload version and starts with 23.195. as its first two octets
  3. If the version is newer than the current one, the masked IP address is de-masked, resulting in a real command-and-control (C&C) IP address
  4. The real C&C IP address is used along with a hardcoded constant string (part of a URL path) to download a file containing malicious shellcode

Some variants of the infection chain stashed the malicious code inside an image file to make them harder to detect. The variants also installed a custom root TLS certificate that satisfied requirements by some targeted systems that all apps must be digitally signed before being installed.

The payload contained multiple backdoors that were activated when installed on large networks. Curiously, the update also delivered XMRig, an open-source package for mining cryptocurrency.

The GuptiMiner infection chain.

Enlarge / The GuptiMiner infection chain.

Avast

GuptiMiner has circulated since at least 2018 and has undergone multiple revisions. One searched compromised networks for systems running Windows 7 and Windows Server 2008, presumably to deliver exploits that worked on those earlier versions. Another provided an interface for installing special-purpose modules that could be customized for different victims. (This version also scanned the local system for stored private keys and cryptocurrency wallets.)

The researchers were surprised that malware that took such pains to fly under the radar would also install a cryptocurrency miner, which by nature is usually easy to detect. One possibility is the attackers’ possible connection to Kimsuky, the tracking name for a group backed by the North Korean government. Over the years, North Korea’s government has generated billions of dollars in cryptocurrency through malware installed on the devices of unwitting victims. The researchers made the possible connection after finding similarities between a known Kimsuky keylogger and code fragments used during the GuptiMiner operation.

The GuptiMiner attack is notable for exposing major shortcomings in eScan that went unnoticed for at least five years. Besides not delivering updates over HTTPS, a medium not susceptible to MitM attacks, eScan also failed to enforce digital signing to ensure updates hadn’t been tampered with before being installed. Representatives of eScan didn’t respond to an email asking why engineers designed the update process this way.

People who use or have used eScan should check the Avast post for details on whether their systems are infected. It’s likely that most reputable AV scanners will also detect this infection.

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Backdoor found in widely used Linux utility breaks encrypted SSH connections

backdoors, Biz & IT, Linux, Security, supply chain attack, xz utils / /

SUPPLY CHAIN ATTACK —

Malicious code planted in xz Utils has been circulating for more than a month.

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Internet Backdoor in a string of binary code in a shape of an eye.

Enlarge / Internet Backdoor in a string of binary code in a shape of an eye.

Getty Images

Researchers have found a malicious backdoor in a compression tool that made its way into widely used Linux distributions, including those from Red Hat and Debian.

The compression utility, known as xz Utils, introduced the malicious code in versions ​​5.6.0 and 5.6.1, according to Andres Freund, the developer who discovered it. There are no known reports of those versions being incorporated into any production releases for major Linux distributions, but both Red Hat and Debian reported that recently published beta releases used at least one of the backdoored versions—specifically, in Fedora 40 and Fedora Rawhide and Debian testing, unstable and experimental distributions. A stable release of Arch Linux is also affected. That distribution, however, isn’t used in production systems.

Because the backdoor was discovered before the malicious versions of xz Utils were added to production versions of Linux, “it’s not really affecting anyone in the real world,” Will Dormann, a senior vulnerability analyst at security firm Analygence, said in an online interview. “BUT that’s only because it was discovered early due to bad actor sloppiness. Had it not been discovered, it would have been catastrophic to the world.”

Several people, including two Ars readers, reported that the multiple apps included in the HomeBrew package manager for macOS rely on the backdoored 5.6.1 version of xz Utils. HomeBrew has now rolled back the utility to version 5.4.6. Maintainers have more details available here.

Breaking SSH authentication

The first signs of the backdoor were introduced in a February 23 update that added obfuscated code, officials from Red Hat said in an email. An update the following day included a malicious install script that injected itself into functions used by sshd, the binary file that makes SSH work. The malicious code has resided only in the archived releases—known as tarballs—which are released upstream. So-called GIT code available in repositories aren’t affected, although they do contain second-stage artifacts allowing the injection during the build time. In the event the obfuscated code introduced on February 23 is present, the artifacts in the GIT version allow the backdoor to operate.

The malicious changes were submitted by JiaT75, one of the two main xz Utils developers with years of contributions to the project.

“Given the activity over several weeks, the committer is either directly involved or there was some quite severe compromise of their system,” an official with distributor OpenWall wrote in an advisory. “Unfortunately the latter looks like the less likely explanation, given they communicated on various lists about the ‘fixes’” provided in recent updates. Those updates and fixes can be found here, here, here, and here.

On Thursday, someone using the developer’s name took to a developer site for Ubuntu to ask that the backdoored version 5.6.1 be incorporated into production versions because it fixed bugs that caused a tool known as Valgrind to malfunction.

“This could break build scripts and test pipelines that expect specific output from Valgrind in order to pass,” the person warned, from an account that was created the same day.

One of maintainers for Fedora said Friday that the same developer approached them in recent weeks to ask that Fedora 40, a beta release, incorporate one of the backdoored utility versions.

“We even worked with him to fix the valgrind issue (which it turns out now was caused by the backdoor he had added),” the Ubuntu maintainer said.

He has been part of the xz project for two years, adding all sorts of binary test files, and with this level of sophistication, we would be suspicious of even older versions of xz until proven otherwise.

Maintainers for xz Utils didn’t immediately respond to emails asking questions.

The malicious versions, researchers said, intentionally interfere with authentication performed by SSH, a commonly used protocol for connecting remotely to systems. SSH provides robust encryption to ensure that only authorized parties connect to a remote system. The backdoor is designed to allow a malicious actor to break the authentication and, from there, gain unauthorized access to the entire system. The backdoor works by injecting code during a key phase of the login process.

“I have not yet analyzed precisely what is being checked for in the injected code, to allow unauthorized access,” Freund wrote. “Since this is running in a pre-authentication context, it seems likely to allow some form of access or other form of remote code execution.”

In some cases, the backdoor has been unable to work as intended. The build environment on Fedora 40, for example, contains incompatibilities that prevent the injection from correctly occurring. Fedora 40 has now reverted to the 5.4.x versions of xz Utils.

Xz Utils is available for most if not all Linux distributions, but not all of them include it by default. Anyone using Linux should check with their distributor immediately to determine if their system is affected. Freund provided a script for detecting if an SSH system is vulnerable.

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