Ransomware Research



BASS-FES was first discovered in November 2017 in enterprise cloud environments.

First Seen November 2017


To better understand BASS-FES, we can trace it’s origins. Below is a snapshot of BASS-FES’s genealogy.

HiddenTear » BASS-FES

Behavior of BASS-FES

BASS-FES is known to target specific file types. Below are all known file types that BASS-FES is known to infect.

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

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Characteristics of BASS-FES

Here are some of the unique characteristics that are helpful to know about BASS-FES.


Some ransomware will change or append a suffix to the end of the file after they are encrypted, including changing the extension of a file. Here are some of the possible suffixes that BASS-FES ransomware is known to change.


Ransomware Notes

Not all ransomware leaves a note. However, some ransomware leaves the infected party instructions on what the user should do to get rid of the ransomware, or satisfy the ransom. This often involves transferring money, often bitcoin or another cryptocurrency to a designated wallet.

Below are the type(s) of notes, content, and typical locations where Elastio has found ransom notes from BASS-FES.

File NameBASS File Encryption Service Notice.txt


These are the names of the executables that contain the undetonated ransomware payload for BASS-FES.


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 BASS-FES.

External Pages
  • mailto:bitchasshole@protonmail.com
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