Useful, legitimate software which could possibly be misused for malicious purposes.
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Riskware:W32/mIRC is an Internet Relay Chat (IRC) client that can be silently subverted by malware to become a backdoor. By itself, the program is not malicious.
Malware such asBackdoor:W32/Zapchast and its variants can use malicious configuration files to turn the mIRC-client into a backdoor. The malicious configuration files are detected as Backdoor.IRC.Zapchast.
In addition to subverting the mIRC client, these files will also contain the name of an IRC channel which the mIRC-client will automatically try to join on each startup.
Sometimes, Zapchast variants will use additional batch files which provide added functionality, such as performing registry changes to create a launchpoint for the backdoor. These auxiliary batch files are detected as Trojan.BAT.Zapchast.