Email-Worm.Win32.FunnyPics

Parent class: VirWare

Viruses and worms are malicious programs that self-replicate on computers or via computer networks without the user being aware; each subsequent copy of such malicious programs is also able to self-replicate. Malicious programs which spread via networks or infect remote machines when commanded to do so by the “owner” (e.g. Backdoors) or programs that create multiple copies that are unable to self-replicate are not part of the Viruses and Worms subclass. The main characteristic used to determine whether or not a program is classified as a separate behaviour within the Viruses and Worms subclass is how the program propagates (i.e. how the malicious program spreads copies of itself via local or network resources.) Most known worms are spread as files sent as email attachments, via a link to a web or FTP resource, via a link sent in an ICQ or IRC message, via P2P file sharing networks etc. Some worms spread as network packets; these directly penetrate the computer memory, and the worm code is then activated. Worms use the following techniques to penetrate remote computers and launch copies of themselves: social engineering (for example, an email message suggesting the user opens an attached file), exploiting network configuration errors (such as copying to a fully accessible disk), and exploiting loopholes in operating system and application security. Viruses can be divided in accordance with the method used to infect a computer:

• file viruses
• boot sector viruses
• macro viruses
• script viruses

Any program within this subclass can have additional Trojan functions. It should also be noted that many worms use more than one method in order to spread copies via networks.

Class: Email-Worm

Email-Worms spread via email. The worm sends a copy of itself as an attachment to an email message or a link to its file on a network resource (e.g. a URL to an infected file on a compromised website or a hacker-owned website). In the first case, the worm code activates when the infected attachment is opened (launched). In the second case, the code is activated when the link to the infected file is opened. In both case, the result is the same: the worm code is activated. Email-Worms use a range of methods to send infected emails. The most common are: using a direct connection to a SMTP server using the email directory built into the worm’s code using MS Outlook services using Windows MAPI functions. Email-Worms use a number of different sources to find email addresses to which infected emails will be sent: the address book in MS Outlook a WAB address database .txt files stored on the hard drive: the worm can identify which strings in text files are email addresses emails in the inbox (some Email-Worms even “reply” to emails found in the inbox) Many Email-Worms use more than one of the sources listed above. There are also other sources of email addresses, such as address books associated with web-based email services.

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Platform: Win32

Win32 is an API on Windows NT-based operating systems (Windows XP, Windows 7, etc.) that supports execution of 32-bit applications. One of the most widespread programming platforms in the world.

Description

Technical Details

This virus spreads via the Internet as an attachment to infected messages. The worm itself is a Windows PE EXE file 14136 bytes in size.

Installation

The worm copies itself to the Windows root directory as brsh32.exe:

%WinDir%brsh32.exe

It then registers this file in the Windows system registry as a new service. This ensures that the worm will be launched each time Windows is rebooted on the victim machine:

[HKLMSoftwareMicrosoftWindowsCurrentVersionRunServices]
 "brsh32Service"="%WinDir%brsh32.exe -q"

The worm will:

1. spread via email
2. make remote administration of the victim machine possible via a backdoor

The worm sends itself to email addresses harvested from the victim machine.

When sending infected messages, the worm establishes a direct connection to the recipient's SMTP server.

Email Subject

The message subject is chosen at random from the list below:

• are you ready to enjoy?
• do you wanna laugh out?
• Download funny pics for free!
• download screensavers for free!
• Free pics and screensavers
• free screensaver
• funny pics is online again!
• funnypics special offer
• huff OUT!
• humor OnLine
• hunk of fun!
• Listen to Dr.Fun
• pics & screensavers
• ready? steady? laugh!
• Save your screen!
• what you wanna see?

Email Contents

The message body does not change, and is as follows:

Attachment

The worm sends a copy of itself in the following attachment: %windir%brsh32.exe. However, it disguises this file as a picture from www.funnypics.com.

The attachment name is chosen at random from the list below:

• billBates.scr
• bzzz.scr
• funnyPic.scr
• intelAside.scr
• kennyIsAlive.scr
• mac0s.scr
• matrix-SP.scr
• mrBrown.scr
• nastyPokemon.scr
• paradise.scr
• phantomMenaze.scr
• southPark.scr
• SouthParkOuttaSpace.scr
• starWarz.scr
• waaazUp.scr
• x-filez.scr

Payload

The worm will open a TCP port between 8000 and 8255 (chosen at random) and will listen for commands.

This provides a remote malicious user with full access to the victim machine, making it possible to get information from the victim machine, download, launch and delete files.

Removal instructions

1. Delete the following registry key:
   [HKLMSoftwareMicrosoftWindowsCurrentVersionRunServices]
    "brsh32Service"="%WinDir%brsh32.exe -q"
2. Using Task Manager, stop the process called brsh32.exe.
3. Delete the following file: %WinDir%brsh32.exe.
4. Perform a full scan of your computer (download trial version of Kaspersky Anti-Virus).

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Find out the statistics of the vulnerabilities spreading in your region on statistics.securelist.com