For a while, one of the securitytrends is to integrate information from 3rd-party feeds to improve the detection of suspicious activities. By collecting indicators of compromize[1], other tools may correlate them with their own data and generate alerts on specific conditions. The initial goal is to share as fast as possible new IOCs with peers to improve the detection capability and, maybe, prevent further attacks or infections.
However, the 2016 SANS Incident Response Survey[2] demonstrated that, in many cases, the time to detect a compromise width:501px” />
If your organization is targeted, there are few chances to see your malware sample analysed by security researchers and it may take some time to see new IOCs extracted and distributed via classic channels. Thats why playing retro hunting is also important. I like this name: it comes from a VirusTotal feature that allows the creation of YARA rules and to search backwards for samples that match them. (Note: this is only available to paid subscriptions – VT Intelligence[3])
In the same philosophy, its interesting to perform retro-hunting inyour logs to detect malicious activity that occurred in the past. Here is an example based on MISP and Splunk. The first step is to export interesting IOCs like IP addresses, hostnames or hashesfrom the last day. padding:5px 10px”>
0 0 * * * curl -H Authorization: xxxxxx -k -s
https://misp.xxx.xxx/events/csv/download/false/false/false/Network%20activity/ip-src/true/false/false/1d |
awk -F , { print $5 }| sed -e s/value/src_ip/g /opt/splunk/etc/apps/search/lookups/misp-ip-src.csv
15 0 * * * curl -H Authorization: xxxxxx -k -s
https://misp.xxx.xxx/events/csv/download/false/false/false/Network%20activity/hostname/true/false/false/1d |
awk -F , { print $5 }| sed -e s/value/qclass/g /opt/splunk/etc/apps/search/lookups/misp-hostnames.csv
It is possible to fine tune the query and export IOCs that really matter (TLP:RED, with or without this tag, )
Now, lookup tables are ready to be used on Splunk queries. Exported data are for the last day, lets focus on a larger time period width:798px” />
Now let width:900px” />
You can schedule those searches on a daily basis and generate a notification if at least one hit is detected. If its the case, it could be interesting to start an investigation.
Happy retro hunting!
[1]https://isc.sans.edu/forums/diary/Unity+Makes+Strength/20535/
[2]https://www.sans.org/reading-room/whitepapers/incident/incident-response-capabilities-2016-2016-incident-response-survey-37047
[3]https://www.virustotal.com/intelligence/
Xavier Mertens (@xme)
ISC Handler – Freelance Security Consultant
PGP Key
(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.