BKDR_FLYAGENT.HL
Trojan.Win32.Generic!BT (Sunbelt); Runtime packed fsg (AVG)
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
22,137 bytes
EXE
Yes
27 Jun 2013
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 drops the following copies of itself into the affected system:
- %Program Files%\common files\{malware file name}
(Note: %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).)
It creates the following folders:
- %User Temp%\101875
- %User Temp%\101875\....
(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.)
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
101812 = "%User Temp%\41296.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
rdchelp = "%Program Files%\common files\{malware file name}"
Other System Modifications
This backdoor modifies the following file(s):
- %System%\drivers\etc\hosts
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It deletes the following files:
- %User Temp%\101875\TemporaryFile\TemporaryFile
- %Temp%\scs9.tmp
- %Temp%\scsC.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.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)
It deletes the following folders:
- %User Temp%\101875\TemporaryFile
(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\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
101812 = "%User Temp%\41296.exe"
HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
DisableCMD = "0"
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run\
korer
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run\
krero
Dropping Routine
This backdoor drops the following files:
- %User Temp%\41296.exe
- %System%\drivers\etc\hosts.ics
(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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://pv.{BLOCKED}u.com/cityjson?ie=gb2312
- http://heiyingshuai89.{BLOCKED}p.netother/goods/count.asp
- http://heiyingshuai89.{BLOCKED}p.net/fcg-bin/cgi_get_portrait.fcg?uins=2942267549&get_nick=1
- http://heiyingshuai89.{BLOCKED}p.net/tongji.tj
- http://heiyingshuai89.{BLOCKED}p.net/klbvkicbvpabehe/item/1aaa30b05c5a3776bb0e1202
This report is generated via an automated analysis system.
SOLUTION
9.300
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 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
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows
- System
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
- 101812 = "%User Temp%\41296.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- rdchelp = "%Program Files%\common files\{malware file name}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- 101812 = "%User Temp%\41296.exe"
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System
- DisableCMD = "0"
Step 5
Search and delete these components
- %User Temp%\41296.exe
- %System%\drivers\etc\hosts.ics
Step 6
Search and delete these folders
- %User Temp%\101875
- %User Temp%\101875\....
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FLYAGENT.HL. 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 deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %System%\drivers\etc\hosts
Step 9
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%\101875\TemporaryFile\TemporaryFile
- %Temp%\scs9.tmp
- %Temp%\scsC.tmp
Step 10
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\Run
- korer
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- krero
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