Licat.C

Classification

Trojan

Backdoor

Win32

W32/Licat-C, Worm/Licat.C.2, IM-Worm.Win32.Licat.c, WORM_LICAT.C, W32/Licat.C

Summary

Licat.C, a variant of Licat, is a Trojan. Licat.C can send instant messages or contact certain websites to inform malware authors about certain events and allows downloading files on the infected computer. Licat.C tries to connect to certain websites on Internet.

Automatic action

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.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database 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.

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Submit a sample

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Technical Details

Licat.C arrives on the system as a downloaded file via a link that is spammed through MSN Messenger. Below is a sample message:

It searches for the location of MSN Messenger installed on the system through the following registry key:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\MSNMSGR.EXE\Path]

When found, it attempts to rename the original MSN Messenger application client to msgs.exe. It then copies itself to the folder using the filename msnmsgr.exe so that it will start each time that MSN Messenger is started by the user. The copy then launches the renamed Messenger file.

Licat.C's backdoor component (some instances are detected as Backdoor.Win32.MSNMaker.v) connects to the following website:

  • https://go.cheap[REMOVED].info/
  • http://go.links4[REMOVED].biz/

This websites contains links to the following malicious IP address:

  • 69.64.38.140

It uses a vulnerability in the meta tag, which has a malicious IP address on its content. Vulnerable web browsers will automatically execute the file when this site is accessed.

When this IP address is accessed, it will again download from the following websites and execute other malware on the system using the following filenames:

  • https://www.uglyphotos.net/[REMOVED] - alfa.exe
  • https://www.uglyphotos.net/[REMOVED] - sprT.exe
  • https://www.uglyphotos.net/[REMOVED] - Xinstall.exe

The downloaded file, sprT.exe, is the one responsible for the pop-up messages spammed through MSN Messenger. This is also detected as IM-Worm.Win32.Licat.c. Below is the pop-up message used:

  • lol check:P http://peopleonline.pe.funpic.de/[removed].PIF

When this URL link is clicked, a copy of Licat.C will be downloaded on the system.

The two other downloaded files are a trojan dropper (Xinstall.exe) and an adware application (alfa.exe) respectively. They are now detected asTrojan-Dropper.Win32.PurityScan.ag and not-a-virus:AdWare.Win32.Softomate.q.