BKDR_CYCBOT.WIB
Backdoor:Win32/Cycbot.G (Microsoft); BackDoor-EXI.gen.i (McAfee); Backdoor.Cycbot!gen3 (Symantec); Backdoor.Win32.Gbot.gry (Kaspersky); Backdoor.Win32.Cycbot.b (v) (Sunbelt); Gen:Heur.Conjar.4 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor 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
Arrival Details
This backdoor 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 backdoor creates the following folders:
- %User Profile%\CryptnetUrlCache\MetaData
- %User Profile%\Microsoft\CryptnetUrlCache
- %User Profile%\CryptnetUrlCache\Content
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
conhost = "%User Profile%\Microsoft\conhost.exe"
Other System Modifications
This backdoor deletes the following folders:
- %User Profile%\My Documents\My Pictures
- %Start Menu%\Programs\Administrative Tools
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher
HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates
HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\CRLs
HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\CTLs
HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher
HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
Certificates
HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
CRLs
HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
CTLs
Dropping Routine
This backdoor drops the following files:
- %User Profile%\Microsoft\conhost.exe
- %User Profile%\MetaData\2BF68F4714092295550497DD56F57004
- %User Profile%\Content\2BF68F4714092295550497DD56F57004
- %User Profile%\MetaData\94308059B57B3142E455B38A6EB92015
- %User Profile%\Content\94308059B57B3142E455B38A6EB92015
- %User Profile%\MetaData\60E31627FDA0A46932B0E5948949F2A5
- %User Profile%\Content\60E31627FDA0A46932B0E5948949F2A5
- %User Profile%\MetaData\0797C381B2F87EB5A1D5573BD15BA4F4
- %User Profile%\Content\0797C381B2F87EB5A1D5573BD15BA4F4
- %Temp%\c62e.mst
- %User Profile%\MetaData\7B2238AACCEDC3F1FFE8E7EB5F575EC9
- %User Profile%\Content\7B2238AACCEDC3F1FFE8E7EB5F575EC9
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)
This report is generated via an automated analysis system.
SOLUTION
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
Restart in Safe Mode
Step 3
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\Microsoft\SystemCertificates
- TrustedPublisher
- In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher
- Certificates
- In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher
- CRLs
- In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher
- CTLs
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\SystemCertificates
- TrustedPublisher
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\SystemCertificates\TrustedPublisher
- Certificates
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\SystemCertificates\TrustedPublisher
- CRLs
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\SystemCertificates\TrustedPublisher
- CTLs
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- conhost = "%User Profile%\Microsoft\conhost.exe"
Step 5
Search and delete these files
- %User Profile%\Microsoft\conhost.exe
- %User Profile%\MetaData\2BF68F4714092295550497DD56F57004
- %User Profile%\Content\2BF68F4714092295550497DD56F57004
- %User Profile%\MetaData\94308059B57B3142E455B38A6EB92015
- %User Profile%\Content\94308059B57B3142E455B38A6EB92015
- %User Profile%\MetaData\60E31627FDA0A46932B0E5948949F2A5
- %User Profile%\Content\60E31627FDA0A46932B0E5948949F2A5
- %User Profile%\MetaData\0797C381B2F87EB5A1D5573BD15BA4F4
- %User Profile%\Content\0797C381B2F87EB5A1D5573BD15BA4F4
- %Temp%\c62e.mst
- %User Profile%\MetaData\7B2238AACCEDC3F1FFE8E7EB5F575EC9
- %User Profile%\Content\7B2238AACCEDC3F1FFE8E7EB5F575EC9
Step 6
Search and delete these folders
- %User Profile%\CryptnetUrlCache\MetaData
- %User Profile%\Microsoft\CryptnetUrlCache
- %User Profile%\CryptnetUrlCache\Content
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_CYCBOT.WIB. 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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