On Wed, 3 Jan 2001, D. Scott Barninger wrote:

> Hello,
>
> I am still trying to determine all that has been done but here is what I
> know at the moment. If anyone has seen similar attacks please let me
> know what to look for. For starters there appears to be a trojanized su
> binary installed. When calling su there is a delay of approximately 6-8
> seconds after entering the root password before a shell prompt is
> returned. A log message indicates that "call_pam_xauth" successfully
> forked a child (returned 1). At that point a check on the /dev directory
> shows most everything has altered user/group and/or permissions. The tty
> from which the su command was issued is now owned by my user rather than
> root as well as /dev/hdb. /dev/tty* is now writeable by group etc.
> Reinstalling the dev and sh-utils packages corrects things until the
> next time su is run. The same is true on 2 other boxes from which I
> typically rlogin over the internal network (primary box is a MASQ
> gateway). About 2 days prior to discovering this I got port-scanned and
> logged rejected packets on a netbios port (I did have netbios service
> exposed for remote connections).
>
> Any insights would be greatly appreciated.
>
> Scott
>
This kind of attack is basically a common one. Looks like the attacker
scanned a large block of IPs looking for something vulnerable, and then
some hours laters (or days) it exploited the machines that had a flaw
(unfortunately yours were one of these) and installed a root kit to keep
access for him.

Try a
# rpm --verify -a

to check on your RPM database all files that were changed. You will have a
good look on whats missing/changed. Check the RPM manual to see what the
output means (SUM/Date/Size/etc altered, missing, etc)

Try installing lsof (if installed, install from a secure source) and
checking all binded ports, may be a DDoS Agent running or a Bind Shell.
# lsof -i tcp
# lsof -i udp

Any further help, please contact me at email.

---
Osvaldo J. Filho
Unix Security Specialist
ojaneriproteus.com.br
Proteus Security Systems
http://www.proteus.com.br / http://www.proteus-sec.com
---

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