TROJ_SHYLOCK.A
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Trojan connects to certain URLs using a specific format. If the connection is successful, it may download another file and execute it, thus also exhibiting its malicious routines. During testing, however, the URLs are already inaccessible.
This Trojan may be unknowingly downloaded by a user while visiting malicious websites.
It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.
TECHNICAL DETAILS
372,736 bytes
EXE
Yes
07 Sep 2011
Connects to URLs/IPs
Arrival Details
This Trojan may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This Trojan drops the following copies of itself into the affected system:
- %Application Data%\{random path}\{random name}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- CRXT
- {randomGUID}MX
- MTX_{randomGUID}
It is injected into the following processes running in memory:
- explorer.exe
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
{randomGUID} = %Application Data%\{random path}\{random name}.exe
Other System Modifications
This Trojan adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\BrowserEmulation
TLDUpdates = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1406 = "3"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1609 = "3"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
2500 = "3"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"
Download Routine
This Trojan connects to the following malicious URLs:
- {BLOCKED}sadv.cc
- {BLOCKED}at.cc
- {BLOCKED}sphere.cc
NOTES:
{random GUID} is computed from the computer name SID. {random name} is any file name of executable files in the %System% folder as the file name of its dropped copy.
It connects to the abovementioned URLs using the following format:
- {domain}\ping.html
- {domain}\HJ-UK-4.jpg
If the connection is successful, it may download another file and execute it, thus also exhibiting its malicious routines. During testing, however, the URLs are already inaccessible.
SOLUTION
9.200
8.410.03
07 Sep 2011
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Scan your computer with your Trend Micro product and note files detected as TROJ_SHYLOCK.A
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
- {randomGUID} = %Application Data%\{random path}\{random name}.exe
- {randomGUID} = %Application Data%\{random path}\{random name}.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\BrowserEmulation
- TLDUpdates = 0
- TLDUpdates = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- 1406 = 3
- 1406 = 3
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- 1609 = 3
- 1609 = 3
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- 2500 = 3
- 2500 = 3
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- NoProtectedModeBanner = 1
- NoProtectedModeBanner = 1
Step 5
Search and delete the file detected as TROJ_SHYLOCK.A
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SHYLOCK.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.
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