Manipulating Packet Captures

While capturing traffic at Hack or Halo I realized the timestamps on the packets were off by one hour. Apparently I didn't patch this infrequently used Hacom box for the recent DST change.

I captured traffic using Sguil's log_packets.sh script, which uses Snort to write a new full content trace every hour. For the first round of the contest, the script produced two traces. I combined them using Mergecap, bundled with Wireshark.

richard@neely:/var/tmp/shmoocon2007$ mergecap -w shmoocon_hack_rd1.pcap 
 snort.log.1174770982 snort.log.1174773600

The Capinfos program accompanying Wireshark summarizes the new trace:

richard@neely:/var/tmp/shmoocon2007$ capinfos shmoocon_hack_rd1.pcap
File name: shmoocon_hack_rd1.pcap
File type: Wireshark/tcpdump/... - libpcap
Number of packets: 719534 
File size: 155340234 bytes
Data size: 143827666 bytes
Capture duration: 4587.056482 seconds
Start time: Sat Mar 24 17:17:41 2007
End time: Sat Mar 24 18:34:08 2007
Data rate: 31355.11 bytes/s
Data rate: 250840.89 bits/s
Average packet size: 199.89 bytes

I decided to alter the timestamps using Editcap, also packaged with Wireshark.

richard@neely:/var/tmp/shmoocon2007$ editcap -t 3600 shmoocon_hack_rd1.pcap 
 shmoocon_hack_rd1_timeadj.pcap

Now the timestamps are correct.

richard@neely:/var/tmp/shmoocon2007$ capinfos shmoocon_hack_rd1_timeadj.pcap
File name: shmoocon_hack_rd1_timeadj.pcap
File type: Wireshark/tcpdump/... - libpcap
Number of packets: 719534 
File size: 155340234 bytes
Data size: 143827666 bytes
Capture duration: 4587.056482 seconds
Start time: Sat Mar 24 18:17:41 2007
End time: Sat Mar 24 19:34:08 2007
Data rate: 31355.11 bytes/s
Data rate: 250840.89 bits/s
Average packet size: 199.89 bytes

I'm getting these traces to Shmoo now so they can be shared.

Comments

Anonymous said…
Of course these captures cannot be used as evidence anymore since they've been modified.
7:17 PM
Post a Comment

Popular posts from this blog

Zeek in Action Videos

Image
This is a quick note to point blog readers to my Zeek in Action YouTube video series for the Zeek network security monitoring project .  Each video addresses a topic that I think might be of interest to people trying to understand their network using Zeek and adjacent tools and approaches, like Suricata, Wireshark, and so on.  I am especially pleased with Video 6 on monitoring wireless networks . It took me several weeks to research material for this video. I had to buy new hardware and experiment with a Linux distro that I had not used before -- Parrot .  Please like and subscribe, and let me know if there is a topic you think might make a good video.
Read more

MITRE ATT&CK Tactics Are Not Tactics

Image
Just what are "tactics"? Introduction MITRE ATT&CK  is a great resource, but something about it has bothered me since I first heard about it several years ago. It's a minor point, but I wanted to document it in case it confuses anyone else. The MITRE ATT&CK Design and Philosophy document from March 2020 says the following: At a high-level, ATT&CK is a behavioral model that consists of the following core components: • Tactics, denoting short-term, tactical adversary goals during an attack; • Techniques, describing the means by which adversaries achieve tactical goals; • Sub-techniques, describing more specific means by which adversaries achieve tactical goals at a lower level than techniques; and • Documented adversary usage of techniques, their procedures, and other metadata. My concern is with MITRE's definition of "tactics" as "short-term, tactical adversary goals during an attack," which is oddly recursive. The key word in the tacti...
Read more

New Book! The Best of TaoSecurity Blog, Volume 4

Image
  I've completed the TaoSecurity Blog book series . The new book is  The Best of TaoSecurity Blog, Volume 4: Beyond the Blog with Articles, Testimony, and Scholarship .  It's available now for Kindle , and I'm working on the print edition.  I'm running a 50% off promo on Volumes 1-3 on Kindle through midnight 20 April. Take advantage before the prices go back up. I described the new title thus: Go beyond TaoSecurity Blog with this new volume from author Richard Bejtlich. In the first three volumes of the series, Mr. Bejtlich selected and republished the very best entries from 18 years of writing and over 18 million blog views, along with commentaries and additional material.  In this title, Mr. Bejtlich collects material that has not been published elsewhere, including articles that are no longer available or are stored in assorted digital or physical archives. Volume 4 offers early white papers that Mr. Bejtlich wrote as a network defender, either for technica...
Read more