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Buhti ransomware op uses rebranded LockBit and Babuk payloads

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
CVE-2022-47986
YAML Deserialization RCE in IBM Aspera Faspex

IBM Aspera Faspex, an enterprise high-speed file transfer platform, contains a deserialization flaw (CWE-502) that allows a remote attacker to execute code on the server by supplying crafted input that the application insecurely deserializes as YAML. An attacker who can reach the Faspex application can trigger the flaw and run arbitrary code in the context of the application, potentially leading to full compromise of the hosting server. Any organization running IBM Aspera Faspex is affected, with internet-exposed deployments at greatest risk since they provide direct reachability to the vulnerable application. The flaw is being actively exploited: it was added to CISA's Known Exploited Vulnerabilities catalog on 2023-02-21 with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days (top percentile). No public proof-of-concept is catalogued, but confirmed in-the-wild exploitation makes patching urgent.

Do: Apply IBM's update for Aspera Faspex per vendor instructions as the required action, prioritizing any Faspex instance reachable from the internet; restrict network access (firewall/VPN) until patched. Because ransomware actors have used this flaw, also review Faspex servers for signs of compromise, such as unexpected processes spawned by the application, anomalous requests to Faspex application endpoints, or new accounts and persistence mechanisms.

9.8100% KEV ransomware
  • IBM Aspera Faspex
moderate≈1,000–5,000 Faspex deployments, with on the order of a thousand or more internet-exposed (order-of-magnitude estimate)
CVE-2023-27350
Authentication Bypass Leading to SYSTEM RCE in PaperCut MF/NG

PaperCut MF and PaperCut NG print management software contain an improper access control flaw (CWE-284) in the SetupCompleted class that allows an unauthenticated attacker to bypass authentication and reach internal administrative functionality. The flaw is triggered by sending crafted, unauthenticated requests to the PaperCut application's web interface, without requiring valid user credentials. A successful attacker gains the ability to execute code in the context of the SYSTEM account on the PaperCut server, typically a Windows print server, giving full control of that host. Any organization running PaperCut MF or NG is potentially affected, and exposure is highest where the server's web interface is reachable from the internet or by untrusted networks. Exploitation is confirmed in the wild: CISA added the flaw to the KEV on 2023-04-21 with known ransomware use, and EPSS rates exploitation probability at 100% within 30 days.

Do: Apply the vendor's updates as instructed (this is the required action in CISA KEV) — upgrade PaperCut MF/NG to the patched releases listed in PaperCut's security advisory rather than relying on unpatched installs. Until patched, restrict network access to the PaperCut web/admin interface so it is reachable only from trusted hosts, and check the server for signs of compromise given known ransomware use. Prioritize internet-facing PaperCut servers, which public scans show are exposed in the thousands.

9.8100% KEV ransomware PoC ×3
  • PaperCut MF
  • PaperCut NG
masstens of thousands of organizations (~70k+) and millions of users; thousands of internet-exposed PaperCut servers
Full article421 words · extracted from securityaffairs.com · click to collapse

The recently identified Buhti operation targets organizations worldwide with rebranded LockBit and Babuk ransomware variants.

Researchers from Symantec discovered a new ransomware operation called Buhti (aka Blacktail) that is using LockBit and Babuk variants to target Linux and Windows systems worldwide.

The ransomware operation hasn’t its own ransomware payload, however, it uses a custom information stealer to target specified file types.

The Buhti operation has been active since February 2023, it was initially spotted attacking Linux systems, but later Symantec’s Threat Hunter Team also identified attacks on Windows computers.

The group was observed quickly exploiting recently disclosed vulnerabilities, such as the recently patched PaperCut vulnerability.

In a recent attack against Windows systems, Buhti operators used a payload that is a modified version of the leaked LockBit 3.0 (aka LockBit Black) ransomware. The builder used by the operators was leaked in September 2022 by a disgruntled developer in response to Russian invasion of the Ukraine.

The ransomware appends the .buthi extension to the encrypted files.

The researchers also observed attacks against Linux systems with Golang-based variants of the Babuk ransomware, which was released on hacking forums in September 2021. This variant used in the attacks targets ESXi systems.

The information stealer used by the group is written in Golang, it allows operators to look for specific files (pdf, .php, .png, .ppt, .psd, .rar, .raw, .rtf, .sql, .svg, .swf, .tar, .txt, .wav, .wma, .wmv, .xls, .xml, .yml, .zip, .aiff, .aspx, .docx, .epub, .json, .mpeg, .pptx, .xlsx, .yaml. ) and then store them in a compressed .ZIP archive.

“The tool can be configured via command-line arguments to specify both the directory to search for files of interest in and the name of the output archive. The -o argument in the command line specifies the archive to be created. The -d argument specifies the directory to search for files of interest in.” reads the post published by Symantec.

The attackers exploited the vulnerability in PaperCut NG and MF (CVE-2023-27350) to install Cobalt Strike, Meterpreter, Sliver, AnyDesk, and ConnectWise hacking tools.

In February, the group was observed exploiting a vulnerability in IBM’s Aspera Faspex file-exchange application (CVE-2022-47986).

“While the reuse of leaked payloads is often the hallmark of a less-skilled ransomware operation, Blacktail’s general competence in carrying out attacks, coupled with its ability to recognize the utility of newly discovered vulnerabilities, suggests that it is not to be underestimated.” concludes the report.

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Pierluigi Paganini

(SecurityAffairs – hacking, ransomware)



Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/146700/cyber-crime/buhti-ransomware-rebranded-lockbit-babuk.html