TROJ_KRYPTK.YSQ
TrojanDownloader:Win32/Cutwail.BZ (Microsoft), Trojan.Win32.Cutwail.cyl (Kaspersky), TR/Agent.cczq.34 (Antivir),
Windows
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
66,560 bytes
EXE
02 Jun 2014
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.
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
{8 random characters} = "%System%\{8 random characters}.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{8 random characters} = "%User Profile%\{8 random characters}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\WinNTData
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\WinNTData
prx = "{random values}"
Dropping Routine
This Trojan drops the following files:
- %System%\{8 random characters}.exe
- %User Profile%\{8 random characters}.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is a user's profile folder, where it usually is C:\Documents and Settings\{user name} on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name} on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Other Details
This Trojan connects to the following possibly malicious URL:
- {BLOCKED}.33.125
- {BLOCKED}.36.184
- {BLOCKED}.104.81
It deletes itself after execution.