Free Download Manager Site Compromised to Distribute Linux Malware to Users for 3+ Years

-

A download manager site served Linux users malware that stealthily stole passwords and other sensitive information for more than three years as part of a supply chain attack.

The modus operandi entailed establishing a reverse shell to an actor-controlled server and installing a Bash stealer on the compromised system. The campaign, which took place between 2020 and 2022, is no longer active.

"This stealer collects data such as system information, browsing history, saved passwords, cryptocurrency wallet files, as well as credentials for cloud services (AWS, Google Cloud, Oracle Cloud Infrastructure, Azure)," Kaspersky researchers Georgy Kucherin and Leonid Bezvershenko said.

The website in question is freedownloadmanager[.]org, which, according to the Russian cybersecurity firm, offers a legitimate Linux software called "Free Download Manager," but starting in January 2020, began redirecting some users who attempted to download it to another domain deb.fdmpkg[.]org that served a booby-trapped Debian package.

It's suspected that the malware authors engineered the attack based on certain predefined filtering criteria (say, a digital fingerprint of the system) to selectively lead potential victims to the malicious version. The rogue redirects ended in 2022 for inexplicable reasons.

The Debian package contains a post-install script that's executed upon its installation to drop two ELF files, /var/tmp/bs and a DNS-based backdoor (/var/tmp/crond) that launches a reverse shell to a command-and-control (C2) server, which is received in response to a DNS request to one of the four domains -

  • 2c9bf1811ff428ef9ec999cc7544b43950947b0f.u.fdmpkg[.]org
  • c6d76b1748b67fbc21ab493281dd1c7a558e3047.u.fdmpkg[.]org
  • 0727bedf5c1f85f58337798a63812aa986448473.u.fdmpkg[.]org
  • c3a05f0dac05669765800471abc1fdaba15e3360.u.fdmpkg[.]org

"The communication protocol is, depending on the connection type, either SSL or TCP," the researchers said. "In the case of SSL, the crond backdoor launches the /var/tmp/bs executable and delegates all further communications to it. Otherwise, the reverse shell is created by the crond backdoor itself."

The ultimate goal of the attack is to deploy a stealer malware and harvest sensitive data from the system. The collection information is then uploaded to the attacker's server using an uploader binary downloaded from the C2 server.

crond, Kaspersky said, is a variant of a backdoor known as Bew that has been in circulation since 2013, while an early version of the Bash stealer malware was previously documented by Yoroi in June 2019.

It's not immediately clear how the compromise actually took place and what the end goals of the campaign were. What's evident is that not everyone who downloaded the software received the rogue package, enabling it to evade detection for years.

"While the campaign is currently inactive, this case of Free Download Manager demonstrates that it can be quite difficult to detect ongoing cyberattacks on Linux machines with the naked eye," the researchers said.

"Thus, it is essential that Linux machines, both desktop and server, are equipped with reliable and efficient security solutions."


-REFERENCE: https://thehackernews.com/2023/09/free-download-manager-site-compromised.html


-K.Z

Comments

Post a Comment

Popular posts from this blog

CISA and ENISA enhance their Cooperation

-
Image
  The European Union Agency for Cybersecurity (ENISA) has signed a Working Arrangement with the Cybersecurity and Infrastructure Security Agency (CISA) of the US, in the areas of capacity-building, best practices exchange and boosting situational awareness. Geopolitics have shaped the cyber threat landscape, bringing like-minded partners closer together in the wake of common cyber challenges and advances in digital technologies. Today at the EU-US Cyber Dialogue, ENISA and CISA announced the signing of their Working Arrangement as an important milestone in the overall cooperation between the United States and the European Union in the field of cybersecurity, also following the Joint Statement of European Commissioner Thierry Breton and U.S. Secretary for Homeland Security Alejandro Mayorkas of January 2023. ENISA’s International Strategy directs the Agency to be selective in engaging with international partners and to limit its overall approach in international cooperation to those...
Read more

Top Five Most Exploited Vulnerabilities in January 2024

-
Image
In January 2024, cybersecurity faced a remarkable surge in threats, with a focus on exploiting vulnerabilities in technologies from leading vendors. This spike in cyber attacks highlighted the urgent necessity for robust security posture and swift responses to mitigate these vulnerabilities.  Below is an in-depth analysis of the most critical vulnerabilities targeted during January. CVE-2023-46805 and CVE-2024-21887:   CISA Warns Against Ivanti Zero-Day Vulnerabilities On January 19, 2024, the Cybersecurity and Infrastructure Security Agency (CISA) issued an alert regarding two critical zero-day vulnerabilities discovered in Ivanti products:  CVE-2023-46805 and  CVE-2024-21887.  Assigned CVSS scores of 8.2 (High) and 9.1 (Critical), these vulnerabilities underscore a significant risk to cybersecurity, marked by their capability for arbitrary command execution. This prompted an emergency directive for immediate mitigation within federal agencies, highlighting the...
Read more

SmartScreen Vulnerability: CVE-2024-21412 Facts and Fixes

-
Image
On Feb. 13, 2024, Microsoft issued a  patch  for CVE-2024-21412, a  Microsoft Defender SmartScreen  vulnerability revolving around internet shortcuts. Previously, we discovered that an advanced persistent threat (APT) group we track under the name Water Hydra has been exploiting CVE-2024-21412 in a sophisticated campaign targeting financial market traders, allowing the group to bypass Microsoft Defender SmartScreen and infect its victims with the DarkMe remote access trojan (RAT). Threat actors are constantly finding new ways of identifying and exploiting gaps to bypass security measures. We found that the bypass of CVE-2023-36025 (a previously patched SmartScreen vulnerability) led to the discovery and exploitation of CVE-2024-21412. This highlights how threat actors can circumvent patches by identifying new vectors of attack around a patched software component. It is important that organizations are able to identify and mitigate vulnerabilities, especiall...
Read more