RANSOM_COMCIRCLE.A
Ransom.FileCryptor (Malwarebytes), Win32.Trojan.Crypmodadv.Gvm (Tencent), Trojan:Win32/Dynamer!ac (Microsoft)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
386,560 bytes
EXE
Yes
08 Oct 2016
Drops files, Encrypts files
Arrival Details
This Trojan 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 drops and executes the following files:
- %User Temp%\1.exe - screen locker
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Dropping Routine
This Trojan drops the following files:
- {folder of encrypted files}\RESTORE-FILES!{random numbers}.txt - ransom note
Other Details
This Trojan encrypts files with the following extensions:
- .vb
- .scr
- .reg
- .pif
- .msi
- .lnk
- .cpl
- .com
- .cmd
- .bat
- .bas
- .docx
- .pptx
- .xlsx
- .xbap
- .xps
- .pdf
- .pot
- .hta
- .xlt
- .pps
- .xlw
- .dot
- .rtf
- .ppt
- .xls
- .doc
- .xml
- .html
- .htm
- .hta
- .search-ms
- .mht
- .zip
- .dvr-ms
- .wvx
- .wmx
- .wmv
- .wm
- .mpv2
- .mpg
- .mpeg
- .mpe
- .mpa
- .mp2v
- .mp2
- .m1v
- .IVF
- .asx
- .asf
- .wax
- .snd
- .rmi
- .m3u
- .au
- .aiff
- .aifc
- .aif
- .midi
- .mid
- .wma
- .wav
- .mp3
- .wmf
- .tiff
- .tif
- .rle
- .png
- .jpeg
- .jpe
- .jpg
- .jfif
- .ico
- .gif
- .emf
- .dib
- .bmp
It renames encrypted files using the following names:
- {random characters}.comrade
NOTES:
The ransomware displays the following lock screen during encryption:
After encryption, it opens the following ransom note after restarting the computer:
SOLUTION
9.850
12.828.03
08 Oct 2016
12.829.00
09 Oct 2016
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
Step 4
Search and delete this file
- %User Temp%\1.exe
- {folder of encrypted files}\RESTORE-FILES!{random numbers}.txt
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_COMCIRCLE.A. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
Step 6
Restore encrypted files from backup.
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