A system-crashing bug with potential malware implications has been uncovered in Vista. But a fix for the vulnerability, which revolves around flaws in the operating system's network stack, may have to wait until the next service pack.
The TCP/IP stack buffer overflow was discovered by security researchers at Austrian firewall firm Phion in October. Details of the flaw, which also creates a potential mechanism to inject hostile code into vulnerable systems, were disclosed in a posting to BugTraq on Friday.
The vulnerability affects Enterprise and Ultimate versions of Vista in both 32 and 64 bit flavours of the operating system. XP is immune. Phion has published a workaround in the absence of a fix from Microsoft itself.
Exploitation would appear to be tricky and there's no evidence of the misuse of the flaw by hackers. Microsoft has yet to respond to the issue.
Phion's workaround is the first unofficial fix for Vista we're aware of, but its not the first time the issue of unofficial fixes for other vulnerabilities in Microsoft software has arisen. Generally the best advice is to not apply an unofficial fix unless the bug is a real and present danger. The potential damage to the smooth operation of applications more than outweighs the benefits of defending against attacks.
A fix for the flaw from Microsoft is unlikely until the next service pack for Vista, according to Thomas Uterleitner of Phion. No date has been set for the availability of Vista Service Pack 2.
More details on the flaw can be found in a posting on BugTraq here. ®