FortiGuard Labs is aware of a report the infamous BlackCat ransomware group has updated their infostealer tools. Dubbed Exmatter and Eamfo, the former is a data exfiltration tool which a newer version has a code for file corruption and the latter is a credential lifter for Veeam, which is backup software.
Why is this Significant?
This is significant because Blackcat is one of the active Ransomware-as-a-Service (RaaS) providers and their newly updated data exfiltration tool "Exmatter" is now capable of making processed files unusable.
What is BlackCat?
BlackCat, (also known as ALPHV and Noberus), is a relatively new Ransomware-as-a-Service (RaaS) and a ransomware variant with the same name. As a RaaS provider, it develops and offers various tools including ransomware, and recruits affiliates for corporate intrusions, encrypting files on the victim's network and stealing confidential files from it for financial gain. BlackCat ransomware is written in the Rust programming language.
FortiGuard Labs previously released Threat Signal on Blackcat. See the Appendix for a link to "Meet Blackcat: New Ransomware Written in Rust on the Block".
What is Exmatter?
According to security vendor Symantec, Exmatter is a data exfiltration tool that was previously used by a BlackMatter ransomware affiliate. The tool is designed to steal various Microsoft Office files (Word, Excel and PowerPoint) as well as image, email and archive files. It supports FTP, SFTP and WebDav for file transfer of exfiltrated information. The newer version has code to corrupt files.
What is Eamfo?
Eamfo is a tool to steal credentials from Veeam backup software.
What is the Status of Protection?
FortiGuard Labs detects reported Exmatter and Eamfo tools with the following AV signatures:
FortiGuard Labs has the following AV protection in place for known BlackCat ransomware: