BAT_CRYPTOR.A

This ransomware uses the GNU Privacy Guard application, a legitimate app in order to encrypt files.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may arrive bundled with malware packages as a malware component. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan creates the following folders:

• %User Temp%\KEYPRIVATE

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Dropping Routine

This Trojan drops the following files:

• C:\PAYCRYPT_GMAIL_COM.txt
• D:\PAYCRYPT_GMAIL_COM.txt
• %Application Data%\Desktop\PAYCRYPT_GMAIL_COM.txt
• %Desktop%\PAYCRYPT_GMAIL_COM.txt
• %User Temp%\PAYCRYPT_GMAIL_COM.txt
• %User Temp%\pycrp.bin -once this already existed it will not continue its routine

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Other Details

This Trojan encrypts files with the following extensions:

• *.xls
• *.xlsx
• *.doc
• *.docx
• *.pdf
• *.jpg
• *.cd
• *.jpeg
• *.1cd
• *.rar
• *.mdb
• *.zip

It renames encrypted files using the following names:

• {file name and extension}.paycrypt@gmail_com

It deletes itself after execution.

NOTES:

It encrypts file from drives B:\ to Z:\.

The dropped file PAYCRYPT_GMAIL_COM.txt contains the following:

• BLOCK DATE: {Date and time accomplished the encryption}

It deletes the following directory %APPDATA%\gnupg.

It will delete components used in encryption.

When the required components exist, it will dropped the following files:

• %User Temp%\DECODE.zip
• C:\DECODE.zip
• D:\DECODE.zip
• %User Profile%\Desktop\DECODE.zip
• %Application Data%\Desktop\DECODE.zip
• %User Temp%\KEY.PRIVATE
• %User Temp%\KEYPRIVATE\KEY.PRIVATE
• %Application Data%\KEY.PRIVATE
• C:\KEY.PRIVATE
• D:\KEY.PRIVATE
• %Desktop%\KEY.PRIVATE
• %Application Data%\Desktop\KEY.PRIVATE