HackTool - KrbRelay Execution

Severity: high
Author: Florian Roth (Nextron Systems)
Source: upstream

Detects the use of KrbRelay, a Kerberos relaying tool

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1558.003` Steal or Forge Kerberos Tickets: Kerberoasting

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `1 of selection_img`

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

Stage 2: `1 of selection_cli_1`

CommandLine|contains: ' -clsid '
CommandLine|contains: ' -rbcd '
CommandLine|contains: ' -spn '

Stage 3: `1 of selection_cli_2`

CommandLine|contains: clsid
CommandLine|contains: shadowcred
CommandLine|contains: spn

Stage 4: `1 of selection_cli_3`

CommandLine|contains: 'clsid '
CommandLine|contains: 'session '
CommandLine|contains: 'spn '

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`	match	`-clsid` corpus 2 (sigma 2) `-rbcd` `-spn` `clsid` `clsid` `session` `shadowcred` `spn` `spn`
`Image`	ends_with	`\KrbRelay.exe`
`OriginalFileName`	eq	`KrbRelay.exe`

HackTool - KrbRelay Execution

MITRE ATT&CK coverage

Event coverage

Stages and Predicates

Stage 1: 1 of selection_img

Stage 2: 1 of selection_cli_1

Stage 3: 1 of selection_cli_2

Stage 4: 1 of selection_cli_3

Indicators

Stage 1: `1 of selection_img`

Stage 2: `1 of selection_cli_1`

Stage 3: `1 of selection_cli_2`

Stage 4: `1 of selection_cli_3`