When Khaled Mardam-Bey developed an IRC client for the Windows platform, I doubt he envisaged mIRC becoming the basis for the control of an immeasurable number of compromised machines in bot-nets. Khaled has the original authors of the Global-Threat (GT) bot to thank for that.
The original GT bot exploited mIRC’s powerful scripting language, which included support for raw socket connections, to create a bot that was easily controllable via IRC. Functionality included, but was not limited to, port scanning, packet flooding, and provision of BouNCe.
The bot was open source (owing to mIRC’s interpreted scripting) and easily configured. This attribute has allowed it to spawn a myriad of variants, many of which provide completely new functionality.
While the problem is currently understated and difficult to quantify, the trend is definitely on the up. Currently these pervasive bots are displaying worm-like ability and exploiting flaws in Windows or weak security. The two authors of one such variant were arrested in February 2003, with the UK’s National Hi-Tech Crime Unit reporting that over 18,000 computers had been infected.
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Article copyright 2003 Virus Bulletin Ltd (www.virusbtn.com). Permission is granted to Help Net Security to re-print the article.