Core Library Flaws Ripple Through Internet

By Larry Seltzer  |  Posted 2004-09-01 Print this article Print

Opinion: When a popular library such as ASN.1 is hit, the list of victims can be much longer than it seems.

When I read about the serious vulnerabilities in the Kerberos v5 authentication system, one specific aspect of it caught my eye: The lesser of the two issues was related to the ASN.1 library, a library for managing data formats and interchange of data between systems. ASN.1 is a very popular standard and set of libraries used by a vast number of products, both commercial and free. In early 2004, it landed in the news as the object of a series of serious vulnerabilities in Windows, and Check Point had a problem with its ASN.1 libraries later on.

The ASN.1 libraries are really fundamental stuff and need to be as secure as possible. I dont want to rush to the conclusion that the ASN.1 libraries used in these products are badly written, all things considered, but when code is widely used and especially when its used by kernel-level processes, it needs special scrutiny.

When a common library develops a hole, the list of affected products can be immense. Consider the recent PNG (portable network graphics) library bug, the one that affected a large collection of open-source products including Mozilla, ghostscript and perl-tk. These vulnerabilities worry me because the news doesnt necessarily go out that theres a bug in ghostscript, and yet ghostscript users need to upgrade.

For insights on security coverage around the Web, check out Security Center Editor Larry Seltzers Weblog. OpenSSL is another popular program included in many other packages, including just about every Linux and BSD distribution, and it has had several security holes over the past year or two. This one, ironically, has to do with its interaction with ASN.1. In recent years, weve also had a worm targeting OpenSSL and an HTTPS DOS (denial of service) issue in OpenSSL.

I spend a lot of time every day tracking security vulnerability reports, and I have a tough time keeping up with it all. Bugs such as these, in libraries, can create subtle problems that can go completely unnoticed unless the developer happens to be alert and conscientious enough to do something about it.

When a famous product is involved, such as OpenSSL in a Linux distro or libpng in Mozilla, the developers are going to be on top of things. But what about that custom application that a consultant wrote for you? The contract is over, and sure, it would be great if she remembered and let you know, but that would be lucky. I suspect that many silent attacks happen through holes such as these, where no obviously vulnerable products are in use.

There are solutions to problems like this, but they dont come cheaply or easily. Network vulnerability scanners from companies such as eEye can search for vulnerable products on your installation, or you could go it alone and keep track with a good information service such as Symantecs Deepsight Threat Management System. But you at least should be aware that some vulnerability reports may apply to you even if you dont directly use a product of that name. Read the fine print and re-evaluate your systems.

Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983. Check out eWEEK.coms Security Center at 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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