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OpenSSH Local Root Hole
maelstrom writes: "Looks like someone's found a local root exploit for OpenSSH versions between 2.0 and 3.0.2. Seems as though its a one-off error, there is no public exploit, but there is sure to be one shortly. They aren't ruling out remote exploit. Recommending patching and upgrading ASAP."
Script kiddiesprobably has known about this for a while. Full diclosure is not only a way to get the word out so that it can be quickly patched (which apparently it already is) but also a way to kind of force people into an upgrade. That way no one with an old version of ssh is sitting there being unknowingly used for DDOS attacks because they didn't know he needed to upgrade.
Full disclosure has its downsides,but the upsides pretty much cancel them out.
Derek Greene
I'm sure it's more than the last three. Really, how many new features does SSH need? Bugs in an application of this type that is as mature as SSH tend to be security related. It actually makes me feel better that they're quickly responding to security bugs and doing new releases because of it.
Derek Greene
How did it cope with 18,000 simultaneous connections? Did you use mmap(), sendfile() and friends on linux to get the best performance possible? How did the xfer rates compare?
BTW, 24,000 lines is a hell of a lot. If you want to compare like for like, have a look at vsftpd by Chris Evans. It's written entirely in c. Have a read of the source - it's quite interesting how it has been done. I would be surprised if you could find a buffer overflow.
I actually do agree with your points mostly, but I would say "Don't use c for network apps unless you have a good reason to" and also "don't use c for network apps unless you _really_ know the hazards"
In some ways SSH is a special case anyway. It has all the intensive maths stuff to do for the session key generation etc. Not a good idea to code that in (eg.) perl imo.
BTW, out of interest, what is your "favorite modern language" ??
-- MartinG To mail me: echo kewyjlcxyzvjfxbqwh | tr bcefhjklqvwxyz
Did you even look at the patch?
--- channels_old.c Mon Mar 4 02:07:06 2002
+++ channels.c Mon Mar 4 02:07:16 2002
@@ -151,7 +151,7 @@
channel_lookup(int id)
{
Channel *c;
- if (id < 0 || id > channels_alloc) {
+ if (id < 0 || id >= channels_alloc) {
log("channel_lookup: %d: bad id", id);
return NULL;
}
You want to explain to me how any "modern safe language" is going to stop me from saying 'greater-than', when I really mean 'greater-than-or-equal-to'?
Errrrrm
Isn't it a bit dogey just grabbing and installing a binary (rpm) from an untrusted source (ie you) for security software like SSH ?
I'll get my source code from a reputable mirror and compile it myself thanks.
Anyone quoted by a reporter knows how little they understand
Don't believe what you read is the truth.
Yes, I read it. The bug is that they write outside the end of an array.
A modern language would not catch this bug (unless you were using a data structure like a search tree instead of an array). However, it would make it NON-EXPLOITABLE, because a safe language would cause an error (ie, exception) on an out-of-bounds write, not corrupt the heap or stack and allow for an exploit.
After analysis, I can say, that this vulnerability is 4 bytes heap overflow, VERY hard to exploit. Problably only Linux will be affected, because Doug Lea's malloc() depends on control structures located just after malloced buffer.