DJB Announces 44 Security Holes In *nix Software

generationxyu writes "D. J. Bernstein, better known as DJB, has announced the discovery of 44 security holes that were found by students in his course MCS 494: Unix Security Holes this fall at the University of Illinois at Chicago. Vulnerable programs of note include: CUPS, NASM, mpg123, MPlayer, xine-lib, and numerous others. Copies of the notification emails are here. The homework for the course was to find and exploit 10 previously undiscovered security holes in currently deployed Unix software. In a class of 25, 44 security holes seems a bit low. Most of the class failed. I was credited with bsb2ppm (actually libbsb) and jpegtoavi. After 300 hours of work and an A average on the exams, I expect to fail the course."

Comments

Don't just take this lying down, IMO

[Skyshadow]

Now that's a tough assignment. 44 holes found is an average of less than two a person -- it's possible the *entire* class failed, not just most. At best, probably one person completed the assignment.

As much as I respect profs who are willing to push you to do neat things (finding 44 holes in UNIX and it's standard set of programs is nothing to sneeze at), if you really do fail the class I'd take this straight to the administration. They're letting you down by allowing a professor to fail an entire class, especially since the grades are based on something that doesn't really reflect your understanding of the subject.

I've always had a problem with this sort of behavior in college profs -- it gets away from what I consider to be the basic nature of higher education. As a student, I'm the consumer. I'm paying the professor to teach me what he/she knows and then to rate how well I've absorbed that information at the end of the class. Assignments such as this one or classes which are set up as "cut down classes" just aren't consistant with that.

It works the same way on the other end; I had a few professors in college who would cancel class on a fairly routine basis. Hey, I enjoy the odd day off as much as anyone else, but I'm paying a lot of money based on the assumption that I'm going to be getting something in return -- if I were to subscribe to a magazine and then only get 2/3rds of the issues, do you thing I'd be within my rights to object? Hell, the overly easy classes were bad enough; I actually had a few that graded based mostly on attendance. Yeah, getting the most for my tuition dollar there.

Anyhow, I know there are folks out there who are going to disagree with my view of a University education, and that's fine, but regardless I would really encourage you not to accept this lying down. I know as a student it often seems like you're powerless, but if 25 of you (and your parents -- I know you're an adult, but schools listen to parents) get together and make yourselves heard, you'll probably end up with a satisfactory outcome.

Re:Don't just take this lying down, IMO

[edunbar93]

oh lookit me i wrote qmail and its all uber secure

That's cute. His code may not have any bugs in it, but damn, does it ever have some huge logical flaws.

Qmail has the lovely lack of ability to reject e-mail while the SMTP connection is still active. What it does instead is it creates and sends a bounce message itself, instead of leaving that up to the sending server. What happens when you do this is you allow spammers to send e-mail to recipients in the To: line instead of the From: line, just by putting in a bogus To: line and putting the real recipient in the From: line.

There's a patch for this, but it involves setting up a list of e-mail addresses that are allowed to be accepted. Once you have several thousand e-mail addresses all over the place courtesy of Vpopmail, this becomes an impossible task.

So no, this man isn't a perfect programmer.

Students didn't exploit the loophole

[fireboy1919]

He pretty much gave them free reign. ANY OSS at all!

Have you seen CPAN? Half of that code is something someone hacked up in a day! And what about all those sourceforge projects that have one developer and less than 10000 lines?

Meanwhile, almost every piece of code that this class is looking at is stuff that's already had a once over - heck, probably even been looked over thousands of times. No wonder they couldn't find any bugs. They were looking in the houses, not the motels.

Fuzz testing

[ScottMaxwell]

If you want a quick and easy way to find potentially exploitable bugs, try fuzz testing. This is as simple as it could be: feed random data (e.g., from /dev/random) into applications until you crash one. That usually means there's a buffer overflow, which you can then exploit. Re-run the test under a debugger to pinpoint the exact cause of the crash, then craft an attack.

The better approach is to create one or more large files of random data and feed that into the apps; this is better because it gives you a reproducible stream. (Or you can use a Perl script with a known srand() seed.)

The term "fuzz testing" comes from a seminal 1990 paper (and followups in 1995 and 2000) by Barton Miller et al., who, incidentally, found much higher quality in GNU tools than in their proprietary counterparts. Before my tendinitis got too bad, I used to run The Bulletproof Penguin a one-man project devoted to stamping out such bugs (my initial goal, easily achieved, was to eliminate all the bugs reported in the original paper). Ben Woodard was doing something very similar for a while, but I don't know whether he still does.

Incidentally, this makes a certain recent Slashdot story more embarrassing: it seems that free Web browsers crash on malformed input, the kind of case that free software normally handles better than its proprietary competition.

Re:It's just an assignment - Did you even go to un

[SetupWeasel]

That kind of stuff usually doesn't work. In an Astronomy class (toward an Astronomy major, not that gen-ed crap) the professor did not tell us we would have to remember constants, and he asked them as questions. They were short questions, and weren't worth a lot.

One of them was: What is the orbital period of Saturn? (2 pts/100)

I started thinking about Bode's law and the posibility I could calculate it from an approximate radius I would get from that law... if I could remember it. But when you expect a 72% to be an A on a test, you have bigger fish to fry.

Then I got it. It was right, it should work, and no one would have to be nailed to anything.

I wrote: One Saturn-Year

I didn't get credit for it. A couple years later a sophmore was telling me about this funny question he had in the same class. He showed it to me. It read:

What is the orbital period of Saturn? (Do not put one Saturn-Year)

I was so right that it had to be guarded against. Yet those were 2 points I would never have.

Re:Mplayer and Xine new security releases

[iive]

Place mod the parent up.

As one of the mplayer developers, I would like to thank to DJB for giving us (hmm)16 (?) hours before unleashing exploints on wild.

Maybe he is not aware that making right fix, testing it and finally releasing it, is not so simple task. Especially if we have to convice the person that have release (write) permisions, that him girlfriend is not as importan as the security release:)

Not to say, that I still haven't got the mail in my mailbox, despire that gmame shows it have been recived.

Also mplayer-dev-eng@mplayerhq.hu is the more appropriate maillist to send security issues. (MPlayer documentation will be updated accordingly.)

The exploit that is found in MPlayer is not alone. There are at least 2 other places with similar exploitable bahavioud in the same file. I guess the students keep them for next semester.

BTW code originates from Xine, probably it is time to update our version ;)

Re:It's just an assignment - Did you even go to un

[rawb]

Sir Ernest Rutherford, President of the Royal Academy, and recipient of the Nobel Prize in Physics, related the following story.

Some time ago I received a call from a colleague. He was about to give a student a zero for his answer to a physics question, while the student claimed a perfect score. The instructor and the student agreed to an impartial arbiter, and I was selected.

I read the examination question: "Show how it is possible to determine the height of a tall building with the aid of a barometer." The student had answered: "Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of the rope is the height of the building."

The student really had a strong case for full credit since he had really answered the question completely and correctly! On the other hand, if full credit were given, it could well contribute to a high grade in his physics course and certify competence in physics, but the answer did not confirm this.

I suggested that the student have another try. I gave the student six minutes to answer the question with the warning that the answer should show some knowledge of physics. At the end of five minutes, he hadn't written anything. I asked if he wished to give up, but he said he had many answers to this problem; he was just thinking of the best one. I excused myself for interrupting him and asked him to please go on.

In the next minute, he dashed off his answer, which read: "Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, using the formula x=0.5*a*t^2, calculate the height of the building." At this point, I asked my colleague if he would give up. He conceded, and gave the student almost full credit.

While leaving my colleague's office, I recalled that the student had said that he had other answers to the problem, so I asked him what they were.

"Well," said the student, "there are many ways of getting the height of a tall building with the aid of a barometer.

For example, you could take the barometer out on a sunny day and measure the height of the barometer, the length of its shadow, and the length of the shadow of the building, and by the use of simple proportion, determine the height of the building."

"Fine," I said, "and others?"

"Yes," said the student, "there is a very basic measurement method you will like. In this method, you take the barometer and begin to walk up the stairs. As you climb the stairs, you mark off the length of the barometer along the wall. You then count the number of marks, and this will give you the height of the building in barometer units." "A very direct method."

"Of course. If you want a more sophisticated method, you can tie the barometer to the end of a string, swing it as a pendulum, and determine the value of g [gravity] at the street level and at the top of the building. From the difference between the two values of g, the height of the building, in principle, can be calculated."

"On this same tack, you could take the barometer to the top of the building, attach a long rope to it, lower it to just above the street, and then swing it as a pendulum. You could then calculate the height of the building by the period of the precession".

"Finally," he concluded, "there are many other ways of solving the problem. Probably the best," he said, "is to take the barometer to the basement and knock on the superintendent's door. When the superintendent answers, you speak to him as follows: 'Mr. Superintendent, here is a fine barometer. If you will tell me the height of the building, I will give you this barometer."

At this point, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.

The name of the studen

Re:It's just an assignment - Did you even go to un

[entropy_uc]

The best part of that story:

...all of the methods attributed to Bohr are more accurate than the method the professor considered to be the 'right' solution.

(delta P on the barometer will be so small that error in reading the difference will dominate the result)