TROJ_KRYPTIK.YJ
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
It deletes itself after execution.
TECHNICAL DETAILS
176,640 bytes
EXE
No
25 Nov 2013
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:
- %System Root%\malacuxatx.exe\malacuxatx.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It creates the following folders:
- %System Root%\malacuxatx.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Other System Modifications
This Trojan deletes the following files:
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path1
CacheLimit = "13fa6"
(Note: The default value data of the said registry entry is ffac.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path2
CacheLimit = "13fa6"
(Note: The default value data of the said registry entry is ffac.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path3
CacheLimit = "13fa6"
(Note: The default value data of the said registry entry is ffac.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path4
CacheLimit = "13fa6"
(Note: The default value data of the said registry entry is ffac.)
Dropping Routine
This Trojan drops the following files:
- %System Root%\malacuxatx.exe\config.bin
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Other Details
This Trojan deletes itself after execution.
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
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\CurrentVersion\Internet Settings\Cache\Paths\path1
- From: CacheLimit = "13fa6"
To: CacheLimit = ""ffac""
- From: CacheLimit = "13fa6"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2
- From: CacheLimit = "13fa6"
To: CacheLimit = ""ffac""
- From: CacheLimit = "13fa6"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3
- From: CacheLimit = "13fa6"
To: CacheLimit = ""ffac""
- From: CacheLimit = "13fa6"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4
- From: CacheLimit = "13fa6"
To: CacheLimit = ""ffac""
- From: CacheLimit = "13fa6"
Step 3
Search and delete this file
- %System Root%\malacuxatx.exe\config.bin
Step 4
Search and delete this folder
- %System Root%\malacuxatx.exe
Step 5
Scan your computer with your Trend Micro product to delete files detected as TROJ_KRYPTIK.YJ. 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 6
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.
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
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