Threat Description



Category: Malware
Type: Email-Worm
Platform: W32
Aliases: NetSky.Q, W32/Netsky.Q, I-Worm.Netsky.r, W32/Netsky.Q@mm


The Netsky.Q variant was discovered on March 29th, 2004.This worm spreads in email using different exploits and social engineering. NetSky.Q performs a DDoS against several websites and makes the infected computers beep randomly.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:

Technical Details

System Infection

Upon execution the worm copies its dropper to the Windows Directory as 'SysMonXP.exe', which is added to the registry:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] =    "SysMonXP" = "%WinDir%\SysMonXP.exe"  

where %WinDir% represents Windows directory name.

The main DLL is placed to the same place with the filename 'firewallogger.txt' alongside with other temporary files used by the worm:

'zipo0.txt'  'zipo1.txt'  'zipo2.txt'  'zipo3.txt'  'base64.tmp'  'zippedbase64.tmp'  

The worm removes several registry values that belong to other worms.

Email Propagation

When collecting addresses NetSky.Q recursively searches through all hard drives and checks the content of files with the following extensions:

.adb  .asp  .cfg  .cgi  .dbx  .dhtm  .doc  .eml  .htm  .html  .jsp  .mbx  .mdx  .mht  .mmf  .msg  .nch  .ods  .oft  .php  .pl  .ppt  .rtf  .sht  .shtm  .stm  .tbb  .txt  .uin  .vbs  .wab  .wsh  .xls  .xml  

This variant of NetSky sends emails that look like error messages from mail servers.

Here's an example of what messages sent by Netsky.Q can look like:

The emails are composed from the following parts:


Delivery Error   Delivery Failure   Delivery   Mail Delivery failure   Mail Delivery System   Mail System   Delivery   Delivered Message   Error   Status   Failure   Failed   Unknown Exception   Delivery Failed   Deliver Mail   Server Error   Delivery Bot   


Mail Delivery - This mail couldn't be displayed  Mail Delivery Failed - This mail couldn't be represent  Mail Delivery Error - This mail contains unicode characters  Mail Transaction Failed - This mail couldn't be converted  Mail Delivery System - This mail contains binary characters  Mail Delivery Failure - This mail couldn't be shown.  Delivery Failure - Invalid mail specification  Delivery Agent - Translation failed  ------------- failed message -------------  The message has been sent as a binary attachment.  Partial message is available and has been sent as a binary attachment.  Received message has been attached.  Message has been sent as a binary attachment.  Translated message has been attached.  Received message has been sent as an encoded attachment.  Modified message has been sent as a binary attachment.  Note: Received message has been sent as a binary file.  

The attachment name is created from one of the following names:

message  msg  mail  data  

The file extension is either '.pif' or '.zip'. In case of ZIP files the filename inside the ZIP can be one of

data.eml.scr  mail.eml.scr  msg.eml.scr  message.eml.scr  

The purpose of large number of spaces between the extensions is to the hide the executable extension from the users' eyes, leaving them with the harmless looking '.eml' to open.

The email can contain different endings that attempt to start the attachment or make the user to do so.

  • A link with the format: www.<recipient domain>/inmail/<recipient username>/mread.php?sessionid-<random>
  • An exploit for MS01-020 (IFRAME) to execute the attachment automatically. More information on the vulnerability and patches are available from
  • Plain attachment with '.pif' or '.zip' extension

Between 7th and 12th of April, 2004 NetSky.Q infected computers will perform a Distributed Denial-of-Service attack against the following sites:  

On 30th of March, 2004 NetSky.Q will make the infected computer to beep randomly between 5AM and 11AM.


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