ZoneAlarm Bug Bares System To E-Mail Attack

By Larry Seltzer  |  Posted 2004-02-20 Print this article Print

The popular PC personal firewall is subject to buffer overflow and system compromise.

Security vendor Zone Labs has disclosed that several versions of its personal-firewall products are vulnerable to a buffer-overflow attack that could compromise the system. ZoneAlarm, ZoneAlarm Plus and ZoneAlarm Pro 4.0.0 versions; ZoneAlarm Pro 4.5.0; as well as Zone Labs Integrity Client 4.0.0 are vulnerable, the company said. Versions earlier than 4.0.0 are not. ZoneAlarm users are advised to upgrade to Version 4.5.538.001. (See the Zone Labs advisory for more details and how to obtain the upgrades.

The problem was described by eEye Digital Security on the BugTraq mailing list. The firewalls process SMTP (e-mail) traffic sent to or from the system. According to the description, a sufficiently large value in the SMTP "RCPT TO" command can overflow a stack-based buffer in the TrueVector Internet Monitor (vsmon.exe) process.

According to Zone Labs, "If successfully exploited, a skilled attacker could cause the firewall to stop processing traffic, execute arbitrary code, or elevate malicious codes privileges."

An attacker with local access and restricted privileges could invoke the attack by sending an e-mail with the overflowed RCPT TO command. The user could elevate his privileges to SYSTEM level, and a remote user could invoke the attack by manipulating the system into sending an e-mail with the overflow value.

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.

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