PH_Rule_SIGMA_512
Enabled
Shadow Copies deletion using operating systems utilities. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_susp_shadow_copies_deletion.yml
7
Security
Impact
Impact consists of techniques that adversaries use to disrupt availability or compromise integrity by manipulating business and operational processes. Techniques used for impact can include destroying or tampering with data. In some cases, business processes can look fine, but may have been altered to benefit the adversaries’ goals. These techniques might be used by adversaries to follow through on their end goal or to provide cover for a confidentiality breach.
https://attack.mitre.org/tactics/TA0040T1490
Inhibit System Recovery
Adversaries may delete or remove built-in operating system data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery. Operating systems may contain features that can help fix corrupted systems, such as a backup catalog, volume shadow copies, and automatic repair features. Adversaries may disable or delete these system recovery features.
https://attack.mitre.org/techniques/T1490Server
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 "\\diskshadow\.exe$|\\powershell\.exe$|\\pwsh\.exe$|\\vssadmin\.exe$|\\wmic\.exe$" OR srcFileName IN ("PowerShell.EXE","VSSADMIN.EXE","diskshadow.exe","pwsh.dll","wmic.exe")) AND (command REGEXP ".*shadow.*" AND command REGEXP ".*delete.*")) OR ((procName REGEXP "\\wbadmin\.exe$" OR srcFileName="WBADMIN.EXE") AND (command REGEXP ".*delete.*" AND command REGEXP ".*catalog.*" AND command REGEXP ".*quiet.*"))) OR ((procName REGEXP "\\vssadmin\.exe$" OR srcFileName="VSSADMIN.EXE") AND (command REGEXP ".*resize.*" AND command REGEXP ".*shadowstorage.*" AND command REGEXP ".*/MaxSize=.*|.*unbounded.*")))
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
command,hostName,procName,srcFileName
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
command = Filter.command,
hostName = Filter.hostName,
procName = Filter.procName,
srcFileName = Filter.srcFileName