Catb ransomware group
Catb is one of the extortion operations we watch continuously. This page covers what is known about the group and the current state of its leak site.
Who they are
CatB ransomware was first observed in late 2022, gaining attention for abusing DLL hijacking via the Microsoft Distributed Transaction Coordinator (MSDTC) service—loading a malicious payload through DLL sideloading methods. The malware arrives in a two-stage dropper: the first DLL unpacks and launches the main payload (commonly named oci.dll), which subsequently encrypts files using hybrid RSA/AES cryptography. Unlike conventional ransomware, CatB does not rename files or distribute typical ransom notes; instead, it prepends the ransom message directly to the start of each encrypted file, making detection more difficult. Victims are instructed to contact the attackers via email (e.g., [email protected] or [email protected]), with the ransom demand escalating daily. Initial analysis suggests CatB may be a rebrand or evolution of Pandora ransomware, sharing various code artifacts and operational behavior.
Current status
Catb's leak site is not answering. Sites go dark for infrastructure trouble, a deliberate quiet period, or a takedown, and a good number return weeks later under the same name, so the entry stays on the list either way.
Which organisations this group has named, and when, is part of the SINON platform rather than this page. Create an account to search it, or to be told automatically if a name you care about turns up.
Sectors targeted
This group does not state an industry on its site, so we have nothing reliable to report. Most crews are opportunistic rather than sector-specific in any case — they hit what they can reach.
Watching for your name
If Catb posts your company, a supplier or a subsidiary, you want to hear it from us rather than from a journalist. SINON checks these sites continuously and alerts on the names you give it.
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