BKDR_BUTERAT.YHK
Windows
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
990,208 bytes
EXE
Yes
11 Feb 2016
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%\Application Data\LSinglePro
- %User Profile%\LSinglePro\Temporary Internet Files
- %User Profile%\LSinglePro\TFExecuter4
- %User Profile%\LSinglePro\cookies
- %User Profile%\cookies\61362320
- %User Profile%\cookies\58688588
- %User Profile%\cookies\59591878
- %User Profile%\cookies\56459203
(Note: %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.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
GuaZhuan = "{malware path and file name} -autorun "
Other System Modifications
This backdoor modifies the following file(s):
- %Windows%\inf\intl.PNF
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It deletes the following files:
- %User Profile%\LSinglePro\log.txt
(Note: %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.)
It deletes the following folders:
- %System Root%\Temporary Files
- %User Profile%\LSinglePro\Temporary Internet Files
- %User Profile%\LSinglePro\cookies
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\CHtmlDialog\
International
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
It adds the following registry entries:
HKEY_CURRENT_USER\Software\CHtmlDialog\
International
AutoDetect = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Enable = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Size = "a"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
InitHits = "64"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Factor = "14"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International
W2KLpk = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International
W2KLpk = "0"
Dropping Routine
This backdoor drops the following files:
- %User Profile%\TFExecuter4\HLR_cfg.ini.bak
- %User Profile%\TFExecuter4\SearchEngine.ini.bak
- %User Profile%\TFExecuter4\GlobalConfig.ini.bak
- %User Profile%\LSinglePro\blhash.dat.bak
- %User Profile%\LSinglePro\runtask.dat.bak
- %User Profile%\LSinglePro\bts.dat.bak
- %User Profile%\LSinglePro\bts_tm.dat.bak
- %User Profile%\LSinglePro\bts_tmh.dat.bak
- %User Profile%\LSinglePro\bl.dat.bak
(Note: %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.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://ap4.{BLOCKED}ngbao.cn
- http://ap4.{BLOCKED}ngbao.cn/redirect/CFGUpdate?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/{random path}
- http://ap4.{BLOCKED}ngbao.cn/clt/config/cfg_6.5.ini?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/clt/config/cfg_6.5.ini?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/clt/config/SearchEngine_6.5.ini?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/clt/config/GlobalConfig_6.5.ini?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/as/down/clt/config/blhash_6.5.dat?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/as/down/clt/config/blhash_6.5.dat?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/redirect/CFGUpdate?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/clt/config/runtask_6.5.dat?{random characters}
- http://ap2.{BLOCKED}0.com
- http://cltres.{BLOCKED}ngbao.cn/clt/config/runtask_6.5.dat?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/as/down/clt/config/bts.dat?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/as/down/clt/config/bts_tm.dat?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/as/down/clt/config/bts_tm.dat?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/as/down/clt/config/bts_tmh.dat?{random characters}
- http://ap4.{BLOCKED}ngbao.cn/clt/config/bl_6.5.dat?{random characters}
- http://cltres.{BLOCKED}ngbao.cn/clt/config/bl_6.5.dat?{random characters}
- http://ap2.{BLOCKED}ngbao.cn
- {BLOCKED}.110.5
- {BLOCKED}.219.243
- {BLOCKED}0.136.220
- {BLOCKED}208.198
- {BLOCKED}.1.2
- {BLOCKED}.251.251
- {BLOCKED}7.42.34
- {BLOCKED}226.50
- {BLOCKED}.109.136
- {BLOCKED}1.7.190
- {BLOCKED}8.23.144
- {BLOCKED}3.229.5
- {BLOCKED}7.216.183
- {BLOCKED}3.160.200
- {BLOCKED}3.234.21
- {BLOCKED}3.237.3
- {BLOCKED}9.134.224
- {BLOCKED}.139.142
- {BLOCKED}.28.96
- {BLOCKED}.38.32
- {BLOCKED}.221.145
- {BLOCKED}6.22.240
- {BLOCKED}.13.182
- {BLOCKED}9.39.179
- {BLOCKED}0.121.64
- {BLOCKED}.36.106
This report is generated via an automated analysis system.
SOLUTION
9.8
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_CURRENT_USER\Software\CHtmlDialog\
- International
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
- CpMRU
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- GuaZhuan = "{malware path and file name} -autorun "
- In HKEY_CURRENT_USER\Software\CHtmlDialog\International
- AutoDetect = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
- Enable = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
- Size = "a"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
- InitHits = "64"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
- Factor = "14"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
- W2KLpk = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
- W2KLpk = "0"
Step 5
Search and delete these components
- %User Profile%\TFExecuter4\HLR_cfg.ini.bak
- %User Profile%\TFExecuter4\SearchEngine.ini.bak
- %User Profile%\TFExecuter4\GlobalConfig.ini.bak
- %User Profile%\LSinglePro\blhash.dat.bak
- %User Profile%\LSinglePro\runtask.dat.bak
- %User Profile%\LSinglePro\bts.dat.bak
- %User Profile%\LSinglePro\bts_tm.dat.bak
- %User Profile%\LSinglePro\bts_tmh.dat.bak
- %User Profile%\LSinglePro\bl.dat.bak
Step 6
Search and delete these folders
- %User Profile%\Application Data\LSinglePro
- %User Profile%\LSinglePro\Temporary Internet Files
- %User Profile%\LSinglePro\TFExecuter4
- %User Profile%\LSinglePro\cookies
- %User Profile%\cookies\61362320
- %User Profile%\cookies\58688588
- %User Profile%\cookies\59591878
- %User Profile%\cookies\56459203
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BUTERAT.YHK. 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.
- %Windows%\inf\intl.PNF
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 Profile%\LSinglePro\log.txt
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