TROJ_CRYPWALL.UIJ
Backdoor.Win32.Androm.gaoi(Kaspersky);Worm:Win32/Dorkbot.I(Microsoft);Ransom-FTK!09D9EABD9015(McAfee)
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan modifies registry entries to disable various system services. This action prevents most of the system functions to be used.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
232,960 bytes
EXE
Yes
20 Feb 2015
Installation
This Trojan drops the following copies of itself into the affected system:
- %System Root%\{random}\{random}.exe
- %Application Data%\{random}.exe
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
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} = {random}.exe
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = %Application Data%\{random}.exe
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\{random}.exe
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\{UID}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{RSA PUBLIC KEY} "
HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.TXT}"
HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.HTML}"
HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.LNK}"
HKEY_CURRENT_USER\Software\{UID}\
{random key}
{Path and file of encrypted file} = "{hex values}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = 1
It modifies registry entries to disable the following system services:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ERSvc
Start = 4
(Note: The default value data of the said registry entry is 2.)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BITS
Start = 4
(Note: The default value data of the said registry entry is 2.)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wuauserv
Start = 4
(Note: The default value data of the said registry entry is 2.)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wscsvc
Start = 4
(Note: The default value data of the said registry entry is 2.)
Other Details
This Trojan connects to the following possibly malicious URL:
- {BLOCKED}s.org/img4.php
- {BLOCKED}ia.net/img5.php
- {BLOCKED}group.com/img1.php
- {BLOCKED}a87.com/img2.php
- {BLOCKED}ir.net/img3.php
- {BLOCKED}er.com/img4.php
- {BLOCKED}anhnghiep.net/img5.php
- {BLOCKED}ngforcaregivers.com/img1.php
- {BLOCKED}xation.com/img2.php
- {BLOCKED}x.net/img3.php
- {BLOCKED}ak.org/img4.php
- {BLOCKED}og.net/img5.php
- {BLOCKED}ic.com/img1.php
- {BLOCKED}arn.com/img2.php
- {BLOCKED}owered.net/img3.php
- {BLOCKED}a.com/img4.php
- {BLOCKED}-host.com/img5.php
- {BLOCKED}m.com/img1.php
- {BLOCKED}y.com/img2.php
- {BLOCKED}rading.com/img3.php
- {BLOCKED}surs.net/img4.php
- {BLOCKED}ioncheck.com/img5.php
- {BLOCKED}e.net.ua/img1.php
- {BLOCKED}ineral.com/img/img2.php
- {BLOCKED}edauction.info/wp-content/img3.php
- {BLOCKED}el.com/img4.php
- {BLOCKED}n.org/misc/img5.php
- {BLOCKED}ing.net/img1.php
- {BLOCKED}r.info/img2.php
- {BLOCKED}va.com/robustb/img3.php
- {BLOCKED}tone.com/img4.php
- {BLOCKED}prew.com/slider/img5.php
- {BLOCKED}de.com/word/img1.php
- {BLOCKED}tech.com/renew/img2.php
- {BLOCKED}etport.com/img3.php
It encrypts files with the following extensions:
- pot
- hta
- xlt
- pps
- xlw
- dot
- rtf
- ppt
- xls
- doc
- xml
- htm
- html
- wmv
- wm
- mpv2
- mpg
- mpeg
- mpe
- mpa
- mp2v
- mpg
- 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 deletes the initially executed copy of itself
NOTES:
This Trojan deletes Windows Shadow Copies using the following command:
vssadmin.exe Delete Shadows /All /Quiet
It drops the following files, instructions for availing the decryption service, to the folders with encrypted files:
- HELP_DECRYPT.HTML
- HELP_DECRYPT.PNG
- HELP_DECRYPT.TXT
- HELP_DECRYPT.LNK
SOLUTION
9.750
11.522.05
18 Feb 2015
11.523.00
18 Feb 2015
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
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.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random} = {random}.exe
- {random} = {random}.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random} = %Application Data%\{random}.exe
- {random} = %Application Data%\{random}.exe
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ERSvc
- From: Start = 4
To: Start = 2
- From: Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BITS
- From: Start = 4
To: Start = 2
- From: Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wuauserv
- From: Start = 4
To: Start = 2
- From: Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc
- From: Start = 4
To: Start = 2
- From: Start = 4
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- From: DisableSR = 1
To: DisableSR = 0
- From: DisableSR = 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
- {UID}
- {UID}
Step 7
Search and delete these files
- HELP_DECRYPT.HTML
- HELP_DECRYPT.PNG
- HELP_DECRYPT.TXT
- HELP_DECRYPT.LNK
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPWALL.UIJ. 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.
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