HackTool - KrbRelayUp Execution

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

Detects KrbRelayUp used to perform a universal no-fix local privilege escalation in Windows domain environments where LDAP signing is not enforced

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1550.003` Use Alternate Authentication Material: Pass the Ticket
Credential Access	`T1558.003` Steal or Forge Kerberos Tickets: Kerberoasting
Lateral Movement	`T1550.003` Use Alternate Authentication Material: Pass the Ticket

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `1 of selection_img`

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

Stage 2: `1 of selection_cli_1`

CommandLine|contains: ' -ComputerName '
CommandLine|contains: ' -Domain '
CommandLine|contains: ' relay '

Stage 3: `1 of selection_cli_2`

CommandLine|contains: ' -sc '
CommandLine|contains: ' krbscm '

Stage 4: `1 of selection_cli_3`

CommandLine|contains: ' -cn '
CommandLine|contains: ' -cp '
CommandLine|contains: ' -d '
CommandLine|contains: ' spawn '

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	`-ComputerName` `-Domain` `-cn` `-cp` `-d` corpus 6 (sigma 6) `-sc` corpus 2 (sigma 2) `krbscm` `relay` corpus 2 (sigma 2) `spawn`
`Image`	ends_with	`\KrbRelayUp.exe`
`OriginalFileName`	eq	`KrbRelayUp.exe`

HackTool - KrbRelayUp 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`