Flaws in Graphics Library Could Bring Attacks

By Larry Seltzer  |  Posted 2004-08-05 Print this article Print

Multiple vulnerabilities in an open-source image format reportedly could allow an attacker to execute arbitrary code in the context of a user viewing a malicious PNG image.

A researcher performing a source-code audit on a popular graphics library has found multiple security vulnerabilities in it that could be used to crash programs or execute attack code. The PNG library (libpng) is a collection of graphics routines to manipulate PNG (portable network graphics) files. PNG (Portable Networks Graphic) is a graphics format that was designed many years ago as an alternative to the still more popular GIF format.

Click here to read about fixes from the Mozilla Foundation and Opera.
According to the advisory, released by the OpenPKG Project, there is "a stack-based buffer overflow in libpng which can be triggered to run arbitrary code by a malicious png file."
A null-pointer error also exists that could be used by a malicious PNG file to crash a program, and several integer overflows that the researcher found could produce a denial of service in the program and the possibility of arbitrary code execution.

For insights on security coverage around the Web, check out eWEEK.com Security Center Editor Larry Seltzers Weblog. Many Linux distributions have issued their own advisories and fixes for the bugs, including the Mozilla foundation, which has issued fixes for the Mozilla and Firefox browsers and the Thunderbird e-mail client.

The maintainer of the library, Glenn Randers-Pehrson, suggested that users download libpng 1.2.6rc1, libpng-1.0.16rc1, as well as an appropriate combo patch from Sourceforge or swrinde. Check out eWEEK.coms Security Center at http://security.eweek.com for security news, views and analysis.

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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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