WORM_KATSLO.A
Trojan-Ransom.Win32.Blocker.lyt (Kaspersky), W32/Blocker.LYT!tr (Fortinet)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm 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
299,008 bytes
EXE
No
27 Nov 2012
Arrival Details
This worm 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 worm drops the following copies of itself into the affected system:
- %User Temp%\13.tmp.exe
(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 drops the following files:
- {Removable Drive}\$REChCLE.BIN
- {Removable Drive}\readme.tat
- {Removable Drive}\destopfini
- {Removable Drive}\vagefile.sys
- {Removable Drive}\thLmbs.db
Other System Modifications
This worm adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {random}.{random}
Other Details
This worm deletes itself after execution.
SOLUTION
9.300
9.558.04
21 Nov 2012
9.559.00
22 Nov 2012
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
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\Internet Explorer\Main
- NoProtectedModeBanner = "1"
- NoProtectedModeBanner = "1"
Step 3
Search and delete these files
- {Removable Drive}\$REChCLE.BIN
- {Removable Drive}\readme.tat
- {Removable Drive}\destopfini
- {Removable Drive}\vagefile.sys
- {Removable Drive}\thLmbs.db
Step 4
Scan your computer with your Trend Micro product to delete files detected as WORM_KATSLO.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.
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