Home / malware Worm:W32/NetSky.V
First posted on 21 August 2010.
Source: SecurityHomeAliases :
There are no other names known for Worm:W32/NetSky.V.
Explanation :
A standalone malicious program which uses computer or network resources to make complete copies of itself. May include code or other malware to damage both the system and the network.
Additional DetailsWorm:W32/Netsky.V does not send itself as an e-mail attachment but uses HTML-encoded emails which exploit a vulnerability known as Microsoft Internet Explorer XML Page Object Type Validation Vulnerability (MS03-040) to try and download and execute itself to a vulnerable host computer.
Netsky.V also performs a Denial-of-Service (DoS) attack against certain sites.
NetSky.V worm was discovered late night on April 14th, 2004. The binary code bears high resemblance to the latest NetSky variant, NetSky.U. Sharing up to approximately 86% of the code.
Some of the worm's text strings are scrambled.
Installation
The worm's file is a packed PE executable of length 19432 bytes. Upon execution, NetSky.V copies itself as EastAV.exe file to Windows folder and adds a startup key for this file into System Registry:
€ [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"KasperskyAVEng" = "%WinDir%\KasperskyAVEng.exe"
where %WinDir% represents Windows folder name.
Propagation (E-mail)
Netsky.V arrives in infected emails but does not use an attachment. It sends HTML emails which exploit vulnerability known as Microsoft Internet Explorer XML Page Object Type Validation Vulnerability (MS03-040) that downloads a HTML page to the host.
This HTML page then uses another vulnerbility, Internet Explorer Object Data Remote Execution (MS03-032), that attempts to download the binary part of the worm using command line ftp client, and executes it.
Further information about these vulnerabilities, including a fix, is available from Microsoft:
€ http://www.microsoft.com/technet/security/bulletin/ms03-032.mspx € http://www.microsoft.com/technet/security/bulletin/ms03-040.mspx
The email harvesting functionality is identical to the variant NetSky.U.
The messages will have any of the following format:
Subject: Mail Delivery Sytem failure
Body: The processing of this message can take a few minutes...
Subject: Mail delivery failed
Body: Converting message. Please wait...
Subject: Server Status failure
Body: Please wait while loading failed message...
Subject: Gateway Status failure
Body: Please wait while converting the message...
Payload
Netsky.V has a payload. It performs a DoS (Denial of Service) attack on the following websites from 22nd to 29th of April 2004:
€ www.cracks.am € www.emule.de € www.kazaa.com € www.freemule.net € www.keygen.us
Detection
Detection of NetSky.V was published on April 15th, 2004 in the following F-Secure Anti-Virus updates:
[FSAV_Database_Version]
Version=2004-04-15_02Last update 21 August 2010
