A malicious user exploited the somewhat open submission structure of Steam's Greenlight section over the weekend to briefly hide malware links in cloned versions of legitimate game pages.

Polygon reports that a Steam user going by the handle bluebunny14 posted copies of pages for five games to the Steam's Greenlight section over the weekend. The cloned pages copied the text, screenshots, and videos of existing Greenlight games, including Melancholy Republic and The Maze, to look exactly like legitimate titles seeking attention in Steam's fan-voting area. But the cloned versions of the pages also included links to purported "beta version" links for the games that instead linked users to what Polygon calls "a known Trojan."

After being posted Sunday, the malicious links were reportedly removed by early Monday, and the cloned game pages themselves reportedly removed by Monday afternoon. "Community members alerted us of the situation over the weekend by flagging the content," said Valve's Doug Lombardi in a statement. "Our Community Moderators responded quickly by removing all malicious links from the fake Greenlight material and then we banned the submissions. We are taking further steps to deal with anyone involved in posting the links. We'd like to thank those who reported the issue in addition to our Community Moderators, and we encourage everyone to report any suspicious activity in the future by using the flag icon located throughout the Steam Community."

Steam Greenlight launched in the summer of 2012 as a clearinghouse allowing the community to vote on game concepts and in-progress projects it would like to see offered for sale on Steam. But the section was quickly flooded with spam submissions for fake and offensive listings, and misleadingly sourced clones of copyrighted and trademarked games.

To "cut down on the noise" of these fraudulent submissions, Valve instituted a one-time, $100 fee for Greenlight developers in September of 2012. "It was obvious after the first weekend that we needed to make some changes to eliminate pranksters while giving folks in the community the ability to focus on 'their kind' of games," Valve UI designer Alden Kroll told Ars at the time. While that fee apparently didn't stop bluebunny14's malicious submissions over the weekend, it will likely slow down the same user from continuing to post more malicious links under different accounts.

Open app marketplaces, like those on many smartphone platforms, are often plagued with fake listings purporting to be popular games and software, sometimes hiding malware behind the legitimate-seeming facade. Since its launch in 2003, though, Steam has cultivated a reputation as a more carefully curated marketplace of the best of the PC gaming marketplace, without risk of viruses or other malware.

Steam's curated image has been diluted somewhat in recent years, though, as the number of games available on the service has skyrocketed, doubling in the last 18 months to encompass over 4,000 distinct titles. Over 3,200 submissions have garnered enough user votes to be officially "greenlit" by Valve in the last two years, and over 570 of those games have been officially released on Steam.