Ransomware Research

About CatB


CatB was first discovered in November 2022 in enterprise cloud environments. CatB is found in environments with a number of different names, including FishA, CatFish, FishCat, Fish-Cat, FishA-CatB, etc. For a full list of all names, please see below.

Name CatB
  • FishA
  • CatFish
  • FishCat
  • Fish-Cat
  • FishA-CatB
First Seen November 2022

Behavior of CatB

CatB is known to target specific file types. Below are all known file types that CatB is known to infect.

In some cases, ransomware will update the modified date, when it encrypts files. CatB updates the last modified date of the file it targets.

Learn More

Characteristics of CatB

Here are some of the unique characteristics that are helpful to know about CatB.


These are the names of the executables that contain the undetonated ransomware payload for CatB.

Executablessvchosts.exe, Catb-35a273df61f4506cdb286ecc40415efaa5797379b16d44c240e3ca44714f945b.dll, 1.dll, oci.dll, svchosts

External Pages

Ransomware often links to external pages such as payment pages, telegram contacts, etc. Below are some of the URLs Elastio has found to be associated with CatB.

External Pages
  • mailto:catb9991@protonmail.com
  • mailto:fisha001@protonmail.com
How Elastio can help

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Elastio is a cloud-native data resilience platform on AWS, providing robust security and assuring the recoverability of critical data in cloud environments.

Elastio protects data from ransomware and malware evading perimeter defenses and mitigates downtime, data loss, and reputational harm for businesses.