Vulnerability in WinZip Could Compromise Security

By Larry Seltzer  |  Posted 2004-02-27 Print this article Print

Security experts reported Friday that older versions of the popular Windows file-compression program have a buffer-overflow vulnerability that an attacker could use to compromise a system.

Security analysts on Friday reported that versions of the popular ZIP file management program WinZip have a serious security flaw. According to security intelligence firm iDefense Inc., an error in the parameter parsing code in these versions "allows remote attackers to execute arbitrary code."

The attacker would have to construct a specially designed MIME archive (with one of .mim, .uue, .uu, .b64, .bhx, .hqx and .xxe extensions) and distribute the file to users, the company explained.
Once opened, the attack would trick WinZip into executing code contained in the attacking file. iDefense said it had a functioning proof-of-concept attack demonstrating the problem.

The malicious file could be distributed by e-mail, on a Web page, or through peer-to-peer networks. Files handled by WinZip are not normally executable, so many users are less-hesitant to launch them, even when they come from unknown sources. This problem makes those files much more inherently dangerous.

According to iDefense, versions 7 and 8, as well as the latest beta of WinZip 9 are vulnerable to this attack. However, the released Version 9 of WinZip is not vulnerable.

In addition to upgrading, users can prevent an attack by turning off automatic handling of these file types by WinZip in Windows Explorer. In Windows XP, choose Tools-Folder Options, select the File Types tab, scroll down to the appropriate file types, and either delete them or reassign file handling to another program. Meanwhile, security experts advised users to be suspicious of these file types, as they are not widely used.

Check out eWEEK.coms Security Center at for security news, views and analysis.
Larry Seltzer has been writing software for and English about computers ever since—,much to his own amazement—,he graduated from the University of Pennsylvania in 1983.

He was one of the authors of NPL and NPL-R, fourth-generation languages for microcomputers by the now-defunct DeskTop Software Corporation. (Larry is sad to find absolutely no hits on any of these +products on Google.) His work at Desktop Software included programming the UCSD p-System, a virtual machine-based operating system with portable binaries that pre-dated Java by more than 10 years.

For several years, he wrote corporate software for Mathematica Policy Research (they're still in business!) and Chase Econometrics (not so lucky) before being forcibly thrown into the consulting market. He bummed around the Philadelphia consulting and contract-programming scenes for a year or two before taking a job at NSTL (National Software Testing Labs) developing product tests and managing contract testing for the computer industry, governments and publication.

In 1991 Larry moved to Massachusetts to become Technical Director of PC Week Labs (now eWeek Labs). He moved within Ziff Davis to New York in 1994 to run testing at Windows Sources. In 1995, he became Technical Director for Internet product testing at PC Magazine and stayed there till 1998.

Since then, he has been writing for numerous other publications, including Fortune Small Business, Windows 2000 Magazine (now Windows and .NET Magazine), ZDNet and Sam Whitmore's Media Survey.

Submit a Comment

Loading Comments...
Manage your Newsletters: Login   Register My Newsletters

Rocket Fuel