PE_MUSTAN.A
Virus:Win32/Morto.A (Microsoft), Worm.Win32.Fipp.a (Kaspersky), W32/Pift (Mcafee),Win32/Morto.A (ESET)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: File infector
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This malware is responsible for high infection numbers in EMEA, NABU, and China.
To get a one-glance comprehensive view of the behavior of this File infector, refer to the Threat Diagram shown below.
This file infector arrives via removable drives. It 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 registry entries related to antivirus programs. Doing this allows this malware to execute its routines without being detected by installed antivirus programs. It creates certain registry entries to disable applications related to security.
It infects by appending its code to target host files.
It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.
TECHNICAL DETAILS
Arrival Details
This file infector arrives via removable drives.
It may arrive via network shares.
It 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 file infector adds the following mutexes to ensure that only one of its copies runs at any one time:
- _PPIftSvc
- _PPIft1
It injects codes into the following process(es):
- lsass.exe
- svchost.exe
Autostart Technique
This file infector registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wmicucltsvc
ImagePath = "%System%\wmicuclt.exe"
Other System Modifications
This file infector adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wmicucltsvc
It adds the following registry entries as part of its installation routine:
HKLM\SYSTEM\Select
v = "{virus code}"
HKLM\SYSTEM\Select
p = "{login passwords}
HKLM\SYSTEM\Select
pu = "{login usernames} - {login passwords}"
HKLM\SYSTEM\Select
ext = "{plugin code obtained from C&C}"
HKLM\SYSTEM\Select
plg = "{plugin code obtained from C&C}"
HKLM\SYSTEM\Select
rmt = "{date and time of execution}"
HKLM\SYSTEM\Select
{ip address of targeted victims} = {date and time of execution}
It deletes the following registry entries related to antivirus and security applications:
HKLM\SOFTWARE\Microsoft\
CurrentVersion\Run
{AntiVirus Application} = "{Path of AntiVirus Application}"
It creates the following registry entries to disable applications related to security:
HKEY_LOCAL_MACHINE\CurrentControlSet\Services
{Security Service} = "4"
File Infection
This file infector infects the following file types:
- 32bit .exe files
It infects by appending its code to target host files.
It avoids infecting folders containing the following strings:
- windows
- winnt
- Outlook
- System Volume Information
- RECYCLER
- Internet Explorer
- Movie Maker
- Messenger
- Common Files
- Microsoft
This is the Trend Micro detection for files infected by:
- PE_MUSTAN.A
Download Routine
This file infector connects to the following malicious URLs:
- e.{BLOCKED}t.com
- e.{BLOCKED}t.in
- e.{BLOCKED}t.net
- {BLOCKED}1.{BLOCKED}g.in
- {BLOCKED}1.{BLOCKED}g.net
- {BLOCKED}1.{BLOCKED}g.net
It accesses the following websites to download files:
- {BLOCKED}.{BLOCKED}s.info/plg3.z
- {BLOCKED}.{BLOCKED}s.info/wp.z
NOTES:
The malware copies %System%\wscript.exe as %System%\wmicuclt.exe. It then infects the file %System%\wmicuclt.exe by injecting itself into the last section of the file.
It infects executable files in the following locations:
- local drives
- removable drives
- network drives
- RDPshare \\tsclient\{a-z}$
- network shares
It infects the executable files in the said locations using the following credentials:
[Username]
- administrator
- admin
- user
- test
[Passwords]
- !@#$
- !@#$%
- !@#$%^
- !@#$%^&*
- !@#$%^&*()
- !@#123
- !@#123456
- !password!
- %u%
- %u%1
- %u%111111
- %u%12
- %u%123
- %u%1234
- %u%123456
- 0
- 000000
- 00000000
- 007
- 1
- 100200
- 110
- 110110
- 111
- 1111
- 11111
- 111111
- 1111111
- 11111111
- 111222
- 112233
- 11223344
- 112358
- 12
- 1212
- 121212
- 123
- 123!@#
- 123123
- 123123123
- 123321
- 1233211234567
- 1234
- 12344321
- 12345
- 123456
- 123456!@#
- 1234567
- 12345678
- 123456789
- 1234567890
- 1234qwer
- 123654
- 123abc
- 123asd
- 123pass
- 123qaz456wsx
- 123qwe
- 1313
- 131313
- 1314520
- 1314521
- 1415926
- 147258
- 147258369
- 159357
- 168168
- 198612
- 1pass
- 1q2w3e
- 1QAZ
- 1qaz2wsx
- 2000
- 2002
- 2003
- 20070315
- 2010
- 2011
- 2012
- 201314
- 2112
- 211314
- 2222
- 222222
- 22222222
- 232323
- 2600
- 3
- 31415926
- 3333
- 333333
- 369
- 4128
- 4321
- 4444
- 5150
- 520
- 5201314
- 520520
- 5211314
- 521521
- 54321
- 5555
- 555555
- 654321
- 6666
- 666666
- 6969
- 696969
- 7
- 7758258
- 7758521
- 7777
- 777777
- 7777777
- 77777777
- 789456
- 888888
- 88888888
- 987654
- 987654321
- 999999
- a
- aaa
- aaaa
- aaaaaa
- abc
- abc123
- abcd
- abcd1234
- access
- adm1n
- Admin
- admin!@#
- admin!@#123
- admin123
- adminadmin
- admini
- administrator
- alpha
- asdf
- asdfghjkl
- baseball
- batman
- computer
- database
- dragon
- enable
- fangyou
- foobar
- football
- fuck
- fuckme
- god
- godblessyou
- harley
- home
- hunter
- ihavenopass
- iloveyou
- Internet
- iwantu
- jennifer
- jordan
- killer
- letmein
- Login
- love
- master
- michael
- mima
- monkey
- mustang
- mypass
- mypass123
- mypassword
- mypc
- mypc123
- oapass
- oapassword
- oracle
- owner
- P@ssW0rd
- pa$$0rd
- pass
- pass0rd
- pass123
- pass123456
- pass123word456
- passpass
- passwd
- password
- password1
- pat
- patrick
- pc
- princess
- pussy
- pw123
- pwd
- qazwsx
- qazwsx123456
- qwer
- qwerty
- qwertyuiop
- ranger
- robert
- rock
- rockyou
- root
- sa
- secret
- server
- sex
- shadow
- soft
- super
- sybase
- tasklist
- temp
- temp123
- test
- test123
- testtest
- thomas
- tigger
- trustno1
- user
- user123
- win
- windows
- windows2000
- windows2003
- windowsxp
- woaini
- woaiwojia
- xp
- xxx
- xxxx
- xxxxx
- xxxxxx
- xxxxxxxx
- yxcv
- zxcv
- zxcvbnm
- zzzzzz
Where {Security Service} are the following:
- 360rp
- AVGIDSAgent
- AVGwd
- AntiVirService
- F-Secure Gatekeeper Handler Starter
- FSMA
- FSORSPClient
- MsMpSvc
- NIS
- PavFnSvr
- RsRavMon
- SavService
- V3 Service
- a2AntiMalware
- amsp
- avast! Antivirus
- avp
- ekrn
- kxesapp
- kxescore
- mcods
- mcshield
- pavsrv
- vsserv
- zhudongfangyu
Where {AntiVirus Application} are the following:
- V3 Session Process
- MSC Microsoft Security Client
- F-Secure Manager
- F-Secure TNB
- a-squared
- IKARUS-GuardX
- ShStatEXE
- Sophos AutoUpdate Monitor
- AVP
- AVG_TRAY
- egui
- 360sd
- 360Tray
- G Data AntiVirus Tray Application
- BDAgent
- BitDefender Antiphishing Helper
- avgnt
- kxesc
- Trend Micro Client Framework
- RavTray
- Sophos AutoUpdate Monitor
- APVXDWIN
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
Scan your computer with your Trend Micro product and note files detected as PE_MUSTAN.A
Step 3
Restart in Safe Mode
Step 4
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\SYSTEM\CurrentControlSet\Services
- wmicucltsvc
- wmicucltsvc
Step 5
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\SYSTEM\Select
- v = "{virus code}"
- v = "{virus code}"
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- p = "{login passwords}
- p = "{login passwords}
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- pu = "{login usernames} - {login passwords}"
- pu = "{login usernames} - {login passwords}"
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- ext = "{plugin code obtained from C&C}"
- ext = "{plugin code obtained from C&C}"
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- plg = "{plugin code obtained from C&C}"
- plg = "{plugin code obtained from C&C}"
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- rmt = "{date and time of execution}"
- rmt = "{date and time of execution}"
- In HKEY_LOCAL_MACHINE\SYSTEM\Select
- {ip address of targeted victims} = {date and time of execution}
- {ip address of targeted victims} = {date and time of execution}
- In HKEY_LOCAL_MACHINE\CurrentControlSet\Services
- {Security Service} = "4"
- {Security Service} = "4"
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_MUSTAN.A. 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 7
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\CurrentVersion\Run
- {AntiVirus Application} = "{Path of AntiVirus Application}"
- {AntiVirus Application} = "{Path of AntiVirus Application}"
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