BKDR_BAYROB.CXC
Windows
![](/vinfo/imgFiles/legend.jpg)
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:
- %System%\yydlybphclhkh
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
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
Protection WWAN Error Audio = "%System%\fclvyfmphdz.exe"
Other System Modifications
This backdoor adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableConfig = "1"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
RPSessionInterval = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
RPGlobalInterval = "0"
(Note: The default value data of the said registry entry is 15180.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
RPLifeInterval = "0"
(Note: The default value data of the said registry entry is 76a700.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
TimerInterval = "0"
(Note: The default value data of the said registry entry is 78.)
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
ShellServiceObjects\{FD6905CE-952F-41F1-9A6F-135D9C6622CC}
Dropping Routine
This backdoor drops the following files:
- %System%\yydlybphclhkh\tst
- %User Temp%\bwsvmgmn14egmpsvrvx6lco.exe
- %System%\yydlybphclhkh\lck
- %User Profile%\RSA\S-1-5-18
- %System%\yydlybphclhkh\rng
- %System%\yydlybphclhkh\run
- %System%\yydlybphclhkh\cfg
- %Temp%\bwsvmgxt0bepmps.exe
- %Temp%\bwsvmgrwqtz9mps.exe
- %Temp%\bwsvmgb104zwmps.exe
- %Temp%\bwsvmg4tpm6zmps.exe
- %Temp%\bwsvmg4tpm70mps.exe
- %Temp%\bwsvmg3l6dj2mps.exe
- %Temp%\bwsvmgcdjky7mps.exe
- %Temp%\bwsvmg33dizsmps.exe
- %Temp%\bwsvmgcksqrjmps.exe
- %Temp%\bwsvmgxkunwumps.exe
- %Temp%\bwsvmgpstjkzmps.exe
- %Temp%\bwsvmgve74gxmps.exe
- %System%\fclvyfmphdz.exe
- %System%\djawaivewnlx.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}.124.153
- {BLOCKED}.215.249
- {BLOCKED}.240.171
This report is generated via an automated analysis system.
SOLUTION
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
Restart in Safe Mode
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Protection WWAN Error Audio = "%System%\fclvyfmphdz.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- DisableConfig = "1"
Step 4
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\SOFTWARE\Microsoft\Security Center
- FirewallDisableNotify = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- FirewallOverride = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- AntiVirusDisableNotify = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- AntiVirusOverride = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- DisableSR = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- RPSessionInterval = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- From: RPGlobalInterval = "0"
To: RPGlobalInterval = ""15180""
- From: RPGlobalInterval = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- From: RPLifeInterval = "0"
To: RPLifeInterval = ""76a700""
- From: RPLifeInterval = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- From: TimerInterval = "0"
To: TimerInterval = ""78""
- From: TimerInterval = "0"
Step 5
Search and delete these components
- %System%\yydlybphclhkh\tst
- %User Temp%\bwsvmgmn14egmpsvrvx6lco.exe
- %System%\yydlybphclhkh\lck
- %User Profile%\RSA\S-1-5-18
- %System%\yydlybphclhkh\rng
- %System%\yydlybphclhkh\run
- %System%\yydlybphclhkh\cfg
- %Temp%\bwsvmgxt0bepmps.exe
- %Temp%\bwsvmgrwqtz9mps.exe
- %Temp%\bwsvmgb104zwmps.exe
- %Temp%\bwsvmg4tpm6zmps.exe
- %Temp%\bwsvmg4tpm70mps.exe
- %Temp%\bwsvmg3l6dj2mps.exe
- %Temp%\bwsvmgcdjky7mps.exe
- %Temp%\bwsvmg33dizsmps.exe
- %Temp%\bwsvmgcksqrjmps.exe
- %Temp%\bwsvmgxkunwumps.exe
- %Temp%\bwsvmgpstjkzmps.exe
- %Temp%\bwsvmgve74gxmps.exe
- %System%\fclvyfmphdz.exe
- %System%\djawaivewnlx.exe
Step 6
Search and delete this folder
- %System%\yydlybphclhkh
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BAYROB.CXC. 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 8
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\ShellServiceObjects
- {FD6905CE-952F-41F1-9A6F-135D9C6622CC}
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