Suspicious Mstsc.EXE Execution With Local RDP File

Severity: high
Author: Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects potential RDP connection via Mstsc using a local ".rdp" file located in suspicious locations.

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1219.002` Remote Access Tools: Remote Desktop Software

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\mstsc.exe'
OriginalFileName: mstsc.exe

Stage 2: `all of selection_extension`

or:
CommandLine|endswith: .rdp
CommandLine|endswith: '.rdp"'

Stage 3: `all of selection_paths`

or:
CommandLine|contains: ':\Users\Public\'
CommandLine|contains: ':\Windows\System32\Tasks_Migrated '
CommandLine|contains: ':\Windows\System32\spool\drivers\color'
CommandLine|contains: ':\Windows\Tasks\'
CommandLine|contains: ':\Windows\Temp\'
CommandLine|contains: ':\Windows\Tracing\'
CommandLine|contains: '\AppData\Local\Temp\'
CommandLine|contains: '\Downloads\'

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`	ends_with	`.rdp` corpus 2 (sigma 2) `.rdp"` corpus 2 (sigma 2)
`CommandLine`	match	`:\Users\Public\` corpus 14 (sigma 14) `:\Windows\System32\Tasks_Migrated` `:\Windows\System32\spool\drivers\color` `:\Windows\Tasks\` corpus 6 (sigma 6) `:\Windows\Temp\` corpus 15 (sigma 15) `:\Windows\Tracing\` corpus 2 (sigma 2) `\AppData\Local\Temp\` corpus 16 (sigma 16) `\Downloads\` corpus 12 (sigma 12)
`Image`	ends_with	`\mstsc.exe` corpus 5 (sigma 5)
`OriginalFileName`	eq	`mstsc.exe` corpus 4 (sigma 4)