Mandrake Linux Security Advisory : lynx (MDKSA-2005:186-1)
High Nessus Plugin ID 20057
SynopsisThe remote Mandrake Linux host is missing a security update.
DescriptionUlf Harnhammar discovered a remote buffer overflow in lynx versions 2.8.2 through 2.8.5.
When Lynx connects to an NNTP server to fetch information about the available articles in a newsgroup, it will call a function called HTrjis() with the information from certain article headers. The function adds missing ESC characters to certain data, to support Asian character sets. However, it does not check if it writes outside of the char array buf, and that causes a remote stack-based buffer overflow, with full control over EIP, EBX, EBP, ESI and EDI.
Two attack vectors to make a victim visit a URL to a dangerous news server are: (a) *redirecting scripts*, where the victim visits some web page and it redirects automatically to a malicious URL, and (b)
*links in web pages*, where the victim visits some web page and selects a link on the page to a malicious URL. Attack vector (b) is helped by the fact that Lynx does not automatically display where links lead to, unlike many graphical web browsers.
The updated packages have been patched to address this issue.
The previous patchset had a bug in the patches themselves, which was uncovered by Klaus Singvogel of Novell/SUSE in auditing crashes on some architectures.
SolutionUpdate the affected lynx package.