DNS Iquery Exploit logger The net as a whole has been getting knocked over left and right due to the buffer overflow in bind versions. This module watches for Iquery requests going to TCP port 53. The RoTSB exploit always uses a query ID of 31337 so this is parsed for as well.

iquery.nfr - the actual iquery module N-Code

iquery.cfg - the NFR config file for the iquery module

iquery.desc - the NFR description file for the iquery module

Lockd and NFS This module looks for NFS service requests (service 100003) going to port 4045 (lockd). Silicosis must have been playing with the customized nfs-shell that mudge did. hrmmmmm...

lockd.nfr - the actual lockd module N-Code

lockd.cfg - the NFR config file for the lockd module

lockd.desc - the NFR description file for the lockd module

OOB (WinNuke) Module This module looks for the Urgent Pointer == 3, which causes Windows NT and 95 boxes of various patch levels to crash. Commonly referred to as winnuke.

oob.nfr - the actual OOB module N-Code

oob.cfg - the NFR config file for the OOB module

oob.desc - the NFR description file for the OOB module

Statd Exploit Watcher Two very common and widely used exploits are watched for here. The remote shell exploit (tcp)and the link and unlink of files (udp).

statd.nfr - the actual statd module N-Code

statd.cfg - the NFR config file for the statd module

statd.desc - the NFR description file for the statd module

rpc.ttdbserverd Exploit Detector This module looks for a buffer overflow being exploited in Solaris. A widely publicized exploit is available so maybe it is not such a bad idea to start looking for it.

ttdb.nfr - the actual ttdbserverd module N-Code

ttdb.cfg - the NFR config file for the ttdbserverd module

ttdb.desc - the NFR description file for the ttdbserverd module

Malicious web queries the badweb modules look for requests that indicate malicious activity or attempts to exploit known cgi/http vulnerabilities. Current maliciousness watched for includes:

finger watcher - the finger module simply watches and logs finger requests. It becomes interesting to see who is looking at the users on your machines or if people are doing finger bounces / old finger style attacks.

external arp requests - the ext_arp_inside module looks for arp requests asking the response to be sent to an IP address not on the "internal" network(s). This backend accomplishes this by watching for machines being brought up on the wrong networks or potential strange homings of nets/hosts. One of the theories is that when the system first comes live it will gratuitously arp for itself (although Solaris is one of the few systems that does not do this). Another theory is that if another network stub is mis-attached, potentially between network legs that are treated at disparate security levels, you might see arps for a different net’s router with an external network IP in the arp packet.

external networks watcher - This backend watches for external IP addresses initiating connections across your local wire. Suppose you have an internal network setup where you allow people to initiate connections to the outside world but do not allow externally initiated connections to terminate on internal machines (ESTABLISHED in cisco lingo, or maybe some statefull filter like FW1, or ip-fil). Seeing TCP connections from external networks destined to internal machines with the SYN flag set in these situations would indicate a break in perimiter security. In addition, packets with SYN and any other tcp flags set except for RST are flagged as well. This is due to end systems handling them in different ways - to wit: Microsoft NT treats a SYN|FIN as a raw SYN and happily returns a SYN|ACK. This should alert you of more sophisticated attempts to circumvent filters.

land - This backend watches for land packets. These are packets with the same source and dest IP addresses. This should never be seen in the wild. Upon logging it records the ether address so you can hunt down the offender (that is if you are not passing it through your router… tsk tsk tsk!)

rip1 - This backend watches what is being advertised via RIP Version 1. This is advantageous when users "accidentally" dual home internal and external networks and bring their machines live running routed.

rip2 - This backend watches what is being advertised via RIP Version 2. Again, the belief being people should watch for routes being advertised into or out of their network that they are unaware of.

X-Mas Tree Packet Watcher - This backend looks for packets with ALL tcp flags set (ie SYN|FIN|URG|ACK|RST|PSH). These packets should not exist in normal traffic and are almost always endemic of Denial of Service attacks.

xoutside - This backend watches for what appear to be X connections initiated from internal networks directed to external networks. This could be a potential security concern in attempts to bypass statefull packet filters or if only encrypted and authenticated connections are allowed to internal networks and people are pointing unencrypted X sessions outside.

Conclusion:

mudge@l0pht.com

sili@l0pht.com