BKDR_AGENT.FZW
Adware:Win32/Kraddare (Microsoft); Generic BackDoor!1t3 (McAfee); SecurityRisk.Dropper, SecurityRisk.Downldr (Symantec); ARC:NSIS, [qtldquqo.dll]:Backdoor.Win32.Agent.cizl (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)
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.
It deletes itself after execution.
TECHNICAL DETAILS
127,307 bytes
EXE
No
17 Jul 2012
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 Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsm3.tmp
- %Program Files%\qtldquqo
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Other System Modifications
This backdoor deletes the following files:
- %User Temp%\nsm1.tmp
- %User Temp%\nsm3.tmp
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\qtldquqo
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\qtldquqo\Parameters
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\qtldquqo
ver = "20120523"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\qtldquqo\Parameters
ServiceDll = "%Program Files%\qtldquqo\qtldquqo.dll"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{random characters}"
(Note: The default value data of the said registry entry is {random values}.)
Dropping Routine
This backdoor drops the following files:
- %User Temp%\nsm2.tmp
- %User Temp%\nsm3.tmp\System.dll
- %User Temp%\nsm3.tmp\Math.dll
- %User Temp%\nsm3.tmp\InstallAssist.dll
- %Program Files%\qtldquqo\qtldquqo.dll
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://www.{BLOCKED}num.comcounter/mac_proc.php?{random characters}
- http://www.{BLOCKED}num.comcheck_counter.php?{random characters}
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.200
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
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
- qtldquqo
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\qtldquqo
- Parameters
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\qtldquqo
- ver = "20120523"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\qtldquqo\Parameters
- ServiceDll = "%Program Files%\qtldquqo\qtldquqo.dll"
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\Windows NT\CurrentVersion\SvcHost
- From: netsvcs = "{random characters}"
To: netsvcs = ""{random values}""
- From: netsvcs = "{random characters}"
Step 5
Search and delete these components
- %User Temp%\nsm2.tmp
- %User Temp%\nsm3.tmp\System.dll
- %User Temp%\nsm3.tmp\Math.dll
- %User Temp%\nsm3.tmp\InstallAssist.dll
- %Program Files%\qtldquqo\qtldquqo.dll
Step 6
Search and delete these folders
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsm3.tmp
- %Program Files%\qtldquqo
Step 7
Scan your computer with your Trend Micro product to delete files detected as BKDR_AGENT.FZW. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %User Temp%\nsm1.tmp
- %User Temp%\nsm3.tmp
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