Suspicious ArcSOC.exe Child Process

Severity: high
Author: Micah Babinski
Source: upstream

Detects script interpreters, command-line tools, and similar suspicious child processes of ArcSOC.exe. ArcSOC.exe is the process name which hosts ArcGIS Server REST services. If an attacker compromises an ArcGIS Server system and uploads a malicious Server Object Extension (SOE), they can send crafted requests to the corresponding service endpoint and remotely execute code from the ArcSOC.exe process.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059` Command and Scripting Interpreter, `T1203` Exploitation for Client Execution

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation
Security-Auditing	4688	A new process has been created.

Stages and Predicates

Stage 1: `selection`

or:
Image|endswith: '\cmd.exe'
Image|endswith: '\cscript.exe'
Image|endswith: '\mshta.exe'
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'
Image|endswith: '\regsvr32.exe'
Image|endswith: '\rundll32.exe'
Image|endswith: '\wmic.exe'
Image|endswith: '\wscript.exe'
ParentImage|endswith: '\ArcSOC.exe'

Stage 2: `not 1 of filter_main_cmd`

CommandLine: 'cmd.exe /c "ver"'
Image|endswith: '\cmd.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`CommandLine`	eq	`cmd.exe /c "ver"`
`Image`	ends_with	`\cmd.exe` corpus 92 (sigma 92) `\cscript.exe` corpus 64 (sigma 64) `\mshta.exe` corpus 57 (sigma 57) `\powershell.exe` corpus 143 (sigma 143) `\pwsh.exe` corpus 140 (sigma 140) `\regsvr32.exe` corpus 57 (sigma 57) `\rundll32.exe` corpus 76 (sigma 76) `\wmic.exe` corpus 37 (sigma 37) `\wscript.exe` corpus 64 (sigma 64)
`ParentImage`	ends_with	`\ArcSOC.exe`