Security firm Panda Software last week warned that zCodec, which claims to offer "up to 40 percent better (video) quality", is in fact an adware program that can install Trojans, rootkits and other malicious software. zCodec is freely available online and, as of Monday afternoon, was easy enough to find, offering downloads from its own website - zcodec.com. The site uses images from the films Sin City and Pulp Fiction, and claims zCodec will boost audio as well as video quality. "zCodec is a multimedia compressor/decompressor which registers into the Windows collection of multimedia drivers and integrates with any application using DirectShow and Microsoft Video for Windows," the site states.
Panda's advisory last week revealed that the 100KB file is in fact adware, which "downloads and runs files, changes the DNS configuration and monitors accesses to several adult websites". zCodec, formally known as Adware/ZCodec or Adware/EMediacodec, affects most versions of Windows and was first detected last week, Panda said.
When run, the program alters the system's DNS configuration in order to divert traffic to DNS servers of its choice, a technique sometimes used as part of a phishing scam or to rack up clicks for advertising schemes.
zCodec also accesses a particular IP address to randomly select and download one of a collection of files. The files that could be downloaded include Ruins.MB, a Trojan horse that uses rootkit techniques to conceal itself, Panda said. zCodec could also download an online casino program.
A second file launches every time the user starts Internet Explorer and monitors Web usage. Panda said its software can remove zCodec.