Increase in Redline Stealer Observations

THE THREAT

Starting in mid-March 2022, eSentire observed an increase in the deployment of Redline Stealer malware. Redline Stealer is an information stealing malware that was first identified in early 2020. The malware is available for sale on multiple darkweb marketplaces, meaning that it is in active use by a wide variety of threat actor groups. The malware is primarily focused on the theft of browser credentials from infected systems, but it does have the capability to download and execute files from the Internet.

In recent observations, Redline stealer is distributed via Drive-By-Downloads that impersonate legitimate software installers. Organizations are encouraged to review and apply the relevant recommendations provided below.

What we're doing about it

• eSentire MDR for Network detects this threat
• eSentire MDR for Endpoint has multiple detections for the Redline Stealer
• Infrastructure associated with recent Redline Stealer activity is blocked via eSentire’s Global Deny List
• eSentire has conducted global threat hunts for Indicators of Compromise (IoCs) associated with Redline Stealer
• The eSentire Threat Intelligence team is actively tracking this threat for additional details and detection opportunities

What you should do about it

• Conduct security education sessions for employees on a frequent basis
  • Ensure employees are trained to identify and report potentially malicious content
• Use application whitelisting to minimize the likelihood of malicious downloads
• Apply the Principle of Least Privilege for all users [1]
• Protect endpoints against malware
  • Ensure antivirus signatures are up to date
  • Use a Next-Gen AV (NGAV) or Endpoint Detection and Response (EDR) product to detect and contain threats
• Protect accounts with Multi-Factor Authentication (MFA) to limit the value of compromised credentials
• Rotate all user passwords on a frequent schedule (90-day basis)

Additional information

It should be noted that Redline stealer is often bundled with other malicious content. In a recent observation, the malware was delivered along with a malicious browser extension and a backdoor malware.

Redline Stealer was previously delivered via malicious documents in email. In recent campaigns, eSentire has observed Redline stealer being delivered through drive-by-downloads and malicious advertisements for legitimate software. Impersonated software observed by eSentire includes Rufus and Photoshop. External reports [2] [3] [4] claim Redline has also been delivered via trojanzied versions of Viber, WeChat, Nox, Battlefield, Windows 11 Upgrade, Telegram, and Signal.

As Redline Stealer is readily available for sale online, it is being used by a range of different threat actor groups. Notably, Redline Stealer is reported to be used by the Lapsus$ extortion group (DEV-0537) in order to steal victim passwords and session tokens that can be used to gain wide access into victim organizations [5] [6]. Quickly identifying and remediating malware such as Redline Stealer is critical in preventing more serious attacks from occurring, such as extortion or ransomware deployment.

Due to an overlap in TTPs and Indicators of Compromise (IOCs), the eSentire Threat Intelligence team assesses with high confidence that recent incidents are part of the Magnat campaign, previously reported on by Cisco.

For additional background on Redline Stealer malware, see the eSentire report “Cybercriminals Use Malicious Google Ads to Lure Computer Users to Spoofed Signal and Telegram Websites, Infecting them with Info-Stealing Malware” [7].

Indicators of Compromise

References

[1] https://www.cisa.gov/uscert/bsi/articles/knowledge/principles/least-privilege
[2] https://blog.talosintelligence.com/2021/12/magnat-campaigns-use-malvertising-to.html
[3] https://threatresearch.ext.hp.com/redline-stealer-disguised-as-a-windows-11-upgrade/
[4] https://blogs.blackberry.com/en/2021/07/threat-thursday-redline-infostealer
[5] https://www.microsoft.com/security/blog/2022/03/22/dev-0537-criminal-actor-targeting-organizations-for-data-exfiltration-and-destruction/
[6] https://krebsonsecurity.com/2022/03/a-closer-look-at-the-lapsus-data-extortion-group/
[7] https://www.esentire.com/security-advisories/cybercriminals-use-malicious-google-ads-to-lure-computer-users