Classification

Category :

Malware

Type :

-

Aliases :

Bobax, TrojanProxy.Win32.Bobax.a

Summary

Bobax is a new, Sasser-like trojan proxy that uses the MS04-011 (LSASS.EXE) vulnerability to propagate. When instructed to do so it scans random IP addresses for vulnerable computers.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

The Bobax executable is packed with a modified version of UPX.

The strings within its body are encoded using a simple scrambling function.

It opens a HTTP server on the infected machine, to further distribute itself upon infection of new hosts.

When attempting to find new targets, it will probe the port 5000 ( Universal Plug and Play (UPnP) ) , a sign of a machine running Windows XP. If found, it will attempt infection of the target by means of using the LSASS exploit made famous by the Sasser worm.

When Bobax infects a host, the exploit uses HTTP to download the executable from a webserver which listens on a random port on the attacker host. The data is downloaded into a dropper file called 'svc.exe'.

The dropper drops a DLL to the temporary directory with a random name. The DLL is launched by injecting it to Explorer with a technique called DLL Injection. Because the code runs as a thread in Explorer it's not visible as a separate process.

Protect your devices from malware with F‑Secure Total

Protecting your devices from malicious software is essential for maintaining online security. F‑Secure Total makes this easy, helping you to secure your devices in a brilliantly simple way.

  • Award-winning antivirus and malware protection
  • Online browsing, banking, and shopping protection
  • 24/7 online identity and data breach monitoring
  • Unlimited VPN service to safe­guard your privacy
  • Password manager with private data protection
More Support

Community

Ask questions in our Community .

User Guides

Check the user guide for instructions.

Contact Support

Chat with or call an expert.

Submit a Sample

Submit a file or URL for analysis.