WinZip Computing warned last month of a security flaw in WinZip, its compression/decompression tool that runs on the Windows platform. Security firm Secunia has just rated the flaw as "highly critical", the fourth highest out of its five severity levels.
WinZip versions 3.x, 6.x, 7.x, 8.x and 9.x contain vulnerabilities that could allow a remote attacker to execute malicious code. The problem is caused by a flaw in the way WinZip handles command-line inputs, and can be exploited by a malicious hacker to cause a buffer overflow.
WinZip Computing has released a patch, WinZip 9.0 Service Release 1, which it claims will resolve the buffer overflow issue.
Other changes in the patch include the addition of warning messages in some situations. For example, if a user double-clicks on an .EXE file compressed within a Zip file, WinZip will warn that the compressed file could potentially contain a virus.
The company recommends on its Web site that all users upgrade to version 9 to get the fix at no cost. For new users, a free evaluation version of the patch is available, but after 21 days, they would need to pay the $29 licence fee for WinZip.
The company said it was not aware of the vulnerability having been exploited in the wild when it released the patch.
This news comes only a couple of weeks after warnings that a flaw in Winamp, a media application run on Windows, has been exploited by to infect people's computers with spyware. When Secunia released the initial advisory no patch was available and it advised that users switch to another product.
The flaw has now been patched and the latest Secunia advisory, updated on Monday, advises users upgrade to Winamp 5.05.