PH_Rule_SIGMA_398
Enabled
Well-known DNS Exfiltration tools execution. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_dns_exfiltration_tools_execution.yml
7
Security
Command And Control
T1048.001
Exfiltration Over Alternative Protocol: Exfiltration Over Symmetric Encrypted Non-C2 Protocol
Adversaries may steal data by exfiltrating it over a symmetrically encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.
https://attack.mitre.org/techniques/T1048/001T1071.004
Application Layer Protocol: DNS
Adversaries may communicate using the Domain Name System (DNS) application layer protocol to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.
https://attack.mitre.org/techniques/T1071/004T1132.001
Data Encoding: Standard Encoding
Adversaries may encode data with a standard data encoding system to make the content of command and control traffic more difficult to detect. Common data encoding schemes include ASCII, Unicode, hexadecimal, Base64, and MIME. Some data encoding systems may also result in data compression, such as gzip.
https://attack.mitre.org/techniques/T1132/001Server
Windows Sysmon via FortiSIEM Agent
Correlation
No remediation guidance specified
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
Filter
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
eventType="Win-Sysmon-1-Create-Process" AND (procName REGEXP "\\iodine\.exe$" OR procName REGEXP ".*\\dnscat2.*")
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
hostName,procName
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
hostName = Filter.hostName,
procName = Filter.procName