TROJ_SISRON.AK
Trojan:Win32/Sisron (Microsoft); Generic.bfr!ce (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.Genome.tiix (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Agent.27273 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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
24,064 bytes
EXE
No
14 May 2012
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.
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
CertificateRevocation = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonZoneCrossing = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnOnPostRedirect = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Manager = "{malware path and file name}.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
win = "{malware path and file name}"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
init = "{malware path and file name}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Use FormSuggest = "yes"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Use FormSuggest = "yes"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableScriptDebuggerIE = "yes"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Error Dlg Displayed On Every Error = "no"
HKEY_CLASSES_ROOT
.grp = "MSProgramGroup"
HKEY_CLASSES_ROOT
MSProgramGroup = "Microsoft Program Group"
HKEY_CLASSES_ROOT
MSProgramGroup\Shell\Open\Command = "%System%\grpconv.exe %1"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
(Note: The default value data of the said registry entry is 2.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1601 = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Disable Script Debugger = "yes"
(Note: The default value data of the said registry entry is no.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AeDebug
Auto = "0"
(Note: The default value data of the said registry entry is 0.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "Init Application."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "bdg: ..."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "bdg: Done."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: ..."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Renames."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Copies."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Deletes."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Done."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "Uninit Application."
(Note: The default value data of the said registry entry is Uninit Application..)
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
NOHIDDEN
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\SuperHidden\
Policy
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\SuperHidden
Dropping Routine
This Trojan drops the following files:
- %Temp%\Plug.bat
- %Temp%\driver.inf
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://ck.{BLOCKED}rdiscover.com:88/p6.asp?{random characters}
This report is generated via an automated analysis system.
SOLUTION
9.200
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
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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
- Run
Step 3
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\Internet Settings
- WarnonBadCertRecving = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- CertificateRevocation = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- WarnonZoneCrossing = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- WarnOnPostRedirect = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- Manager = "{malware path and file name}.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- win = "{malware path and file name}"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- init = "{malware path and file name}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
- Use FormSuggest = "yes"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Use FormSuggest = "yes"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- DisableScriptDebuggerIE = "yes"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Error Dlg Displayed On Every Error = "no"
- In HKEY_CLASSES_ROOT
- .grp = "MSProgramGroup"
- In HKEY_CLASSES_ROOT
- MSProgramGroup = "Microsoft Program Group"
- In HKEY_CLASSES_ROOT
- MSProgramGroup\Shell\Open\Command = "%System%\grpconv.exe %1"
Step 4
Restore this modified 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\Explorer\Advanced
- From: Hidden = "2"
To: Hidden = ""2""
- From: Hidden = "2"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- SuperHidden = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1601 = "0"
To: 1601 = ""1""
- From: 1601 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- From: Disable Script Debugger = "yes"
To: Disable Script Debugger = ""no""
- From: Disable Script Debugger = "yes"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug
- From: Auto = "0"
To: Auto = ""0""
- From: Auto = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "Init Application."
To: Log = ""Uninit Application.""
- From: Log = "Init Application."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "bdg: ..."
To: Log = ""Uninit Application.""
- From: Log = "bdg: ..."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "bdg: Done."
To: Log = ""Uninit Application.""
- From: Log = "bdg: Done."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: ..."
To: Log = ""Uninit Application.""
- From: Log = "dros: ..."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Renames."
To: Log = ""Uninit Application.""
- From: Log = "dros: Renames."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Copies."
To: Log = ""Uninit Application.""
- From: Log = "dros: Copies."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Deletes."
To: Log = ""Uninit Application.""
- From: Log = "dros: Deletes."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Done."
To: Log = ""Uninit Application.""
- From: Log = "dros: Done."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "Uninit Application."
To: Log = ""Uninit Application.""
- From: Log = "Uninit Application."
Step 5
Search and delete these files
- %Temp%\Plug.bat
- %Temp%\driver.inf
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_SISRON.AK. 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 7
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
- SHOWALL
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
- NOHIDDEN
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder
- Hidden
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\SuperHidden
- Policy
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder
- SuperHidden
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