RANSOM_CRYPTESLA.CBQ163M
Ransom:Win32/Tescrypt!rfn(Microsoft), Win32/Filecoder.TeslaCrypt.K(ESET), Trojan.Cryptolocker.N(Norton)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
368,640 bytes
EXE
Yes
22 Mar 2016
Connects to URLs/IPs, 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 the following copies of itself into the affected system and executes them:
- %My Documents%\{random filename}.exe
(Note: %My Documents% is usually C:\Documents and Settings\{user name}\My Documents on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Documents on Windows Vista and 7.)
It drops the following files:
- Ransom notes:
- {folders containing encrypted files}\+REcovER+{random 5 characters}.txt
- {folders containing encrypted files}\+REcovER+{random 5 characters}.png
- {folders containing encrypted files}\+REcovER+{random 5 characters}.html
- %Desktop%\+REcovER+{random 5 characters}.txt
- %Desktop%\+REcovER+{random 5 characters}.png
- %Desktop%\+REcovER+{random 5 characters}.html
- %My Documents%\+REcovER+{random 5 characters}.txt
- %My Documents%\+REcovER+{random 5 characters}.png
- %My Documents%\+REcovER+{random 5 characters}.html
- %My Documents%\+recover+file.txt
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
_{random characters} = "%System%\cmd.exe /c start %My Documents%\{random filename}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\trueimg
HKEY_CURRENT_USER\Software\{ID}
HKEY_USERS\.DEFAULT\Software\
trueimg
It adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLinkedConnections = "1"
To enable Windows to share network connections
HKEY_CURRENT_USER\Software\trueimg
ID = "{ID}"
HKEY_CURRENT_USER\Software\{ID}
data = "{hex values}"
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}s.org/phsys.php
- http://{BLOCKED}bow.com/phsys.php
- http://{BLOCKED}entrausaha.com/phsys.php
- http://{BLOCKED}legue.com/phsys.php
- http://classemgmt.{BLOCKED}da.com/phsys.php
It does the following:
- It encrypts files in all fixed, removable, and network drives and shares.
- It does not append an extension to the encrypted files.
- It deletes shadow copies
It deletes the initially executed copy of itself
SOLUTION
9.800
12.418.08
22 Mar 2016
12.419.00
23 Mar 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
Scan your computer with your Trend Micro product and note files detected as RANSOM_CRYPTESLA.CBQ163M
Step 4
Restart in Safe Mode
Step 5
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- _{random characters} = "%System%\cmd.exe /c start %My Documents%\{random filename}.exe"
- EnableLinkedConnections = "1"
Step 6
Delete this registry key
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software
- trueimg
- trueimg
- In HKEY_CURRENT_USER\Software
- {ID}
- {ID}
Step 7
Search and delete this file
- %My Documents%\+recover+file.txt
- +REcovER+{random 5 characters}.txt
- +REcovER+{random 5 characters}.png
- +REcovER+{random 5 characters}.html
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CRYPTESLA.CBQ163M. 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 9
Restore encrypted files from backup.
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