TROJ_KRYPTIK.KYE
TrojanDownloader:Win32/Cred.B (Microsoft); Cleaman.e (McAfee); Packed.Generic.360 (Symantec); Packed.Win32.Krap.iu (Kaspersky); Trojan-Downloader.Win32.Cred.b (v) (Sunbelt); Gen:Heur.Conjar.8 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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 Trojan 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 Trojan drops the following copies of itself into the affected system:
- %User Profile%\mshchar.exe
- %User Profile%\Application Data\utilfs.exe
- %User Temp%\getdisk.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
mshchar = "%User Profile%\mshchar.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
mshchar = "%User Profile%\mshchar.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
utilfs = "%User Profile%\Application Data\utilfs.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
utilfs = "%User Profile%\Application Data\utilfs.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\???????????????????????
It adds the following registry entries:
HKEY_CURRENT_USER\???????????????????????
getdisk = "%User Temp%\getdisk.exe"
This report is generated via an automated analysis system.
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
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
- ???????????????????????
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
- mshchar = "%User Profile%\mshchar.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- mshchar = "%User Profile%\mshchar.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- utilfs = "%User Profile%\Application Data\utilfs.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- utilfs = "%User Profile%\Application Data\utilfs.exe"
- In HKEY_CURRENT_USER\???????????????????????
- getdisk = "%User Temp%\getdisk.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_KRYPTIK.KYE. 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.
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