ARJ File Bug Threatens Trend Micro Scanners

By Larry Seltzer  |  Posted 2005-02-24 Print this article Print

Trend Micro issues patches for a bug in the handling of ARJ compressed archive files. Heap overflow could lead to remote code execution.

A bug in ARJ file parsing in Trend Micro virus-scanning products could lead to a heap-based buffer overflow and potentially to the execution of attack code in the context of the scanner. Trend Micro has issued upgrades to version 7.510 of its virus scanning engine (VSAPI).
ARJ is a format for compressed archive files, similar to Zip.
Software to use it is sold by ARJ Software Inc., although it is supported by many third parties. According to the Trend advisory, the companys ARJ file format parser reads file names from the ARJ local header into a 512-byte buffer. But the file names can be oversized, and the Trend engine will copy beyond the end of the buffer. The next operation after copying the file name to the buffer is to assign data to a variable pointed to by an address just beyond the 512 byte buffer. Thus, when the file name overflows the buffer, this assignment operation results in an illegal memory access. Read more here about Britains launch of a Web site aimed at helping computer users avoid damage from online threats. Its possible that a specially crafted ARJ could execute arbitrary code through this method. The bug was originally discovered by Internet Security Systems. Their advisory states that "successful exploitation of this vulnerability could be used to gain unauthorized access to networks and machines being protected by Trend Micro AntiVirus Library product."

Click here to read more about Trend Micro offering a free download and updates for one of the first software products for protecting handheld devices. This revelation follows a similar one from earlier in February in which a similar vulnerability was found in F-Secures virus-scanning of ARJ files. F-Secure issued a similar advisory and fixes. Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at Security Center Editor Larry Seltzers Weblog.
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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