Grey-hat hacker Unu has discovered cross-site scripting vulnerabilities involving Facebook applications, of a type that might be used to distribute Trojan horse malware or launch other hacking attacks.
The Romanian hacker - well known for identifying security flaws in the websites of banks, security firms and the UK parliament - has turned his attention to the social networking site, discovering a series of flaws in applications. Unu has posted screenshots illustrating the flaws he has identified in five apps developed by Newscloud, alongside an advisory that explains the possible ramifications of the flaws.
A variety of attacks are possible - including uploading phpshells, redirects, or infecting pages with Trojan droppers - because the vulnerable applications expose a writeable directory to attack, the hacker explains.
All five apps were developed by Jeff Reifman, a former project engineer at Microsoft who works for Newscloud. Unu said he wasn't targeting Newscloud in particular, rather simply illustrating a more general problem with Facebook app security.
Newscloud blocked access to the affected apps but is yet to respond to our request for comment on the specific security problems reported.
The publication of Unu's advisory comes at the same time as the ongoing Month of Facebook Bugs project, which also aims to highlight the security shortcoming of the social networking site. Unu told El Reg his work had nothing to do with the project, and that the timing was simply a coincidence. ®