HackTool - KrbRelayUp Execution

Status: test
Severity: high
Log source: category process_creation, product windows
Author: Florian Roth (Nextron Systems)
Source: github.com/SigmaHQ/sigma

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

Known false positives

Unlikely

MITRE ATT&CK coverage

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

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: HackTool - KrbRelayUp Execution
id: 12827a56-61a4-476a-a9cb-f3068f191073
status: test
description: Detects KrbRelayUp used to perform a universal no-fix local privilege escalation in Windows domain environments where LDAP signing is not enforced
references:
    - https://github.com/Dec0ne/KrbRelayUp
author: Florian Roth (Nextron Systems)
date: 2022-04-26
modified: 2023-02-04
tags:
    - attack.credential-access
    - attack.t1558.003
    - attack.lateral-movement
    - attack.t1550.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\KrbRelayUp.exe'
        - OriginalFileName: 'KrbRelayUp.exe' # In case the file has been renamed after compilation
    selection_cli_1:
        CommandLine|contains|all:
            - ' relay '
            - ' -Domain '
            - ' -ComputerName '
    selection_cli_2:
        CommandLine|contains|all:
            - ' krbscm '
            - ' -sc '
    selection_cli_3:
        CommandLine|contains|all:
            - ' spawn '
            - ' -d '
            - ' -cn '
            - ' -cp '
    condition: 1 of selection_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith: '\KrbRelayUp.exe'
    - OriginalFileName: 'KrbRelayUp.exe'

Stage 2: `selection_cli_1`

selection_cli_1:
    CommandLine|contains|all:
        - ' relay '
        - ' -Domain '
        - ' -ComputerName '

Stage 3: `selection_cli_2`

selection_cli_2:
    CommandLine|contains|all:
        - ' krbscm '
        - ' -sc '

Stage 4: `selection_cli_3`

selection_cli_3:
    CommandLine|contains|all:
        - ' spawn '
        - ' -d '
        - ' -cn '
        - ' -cp '

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-ComputerName` `-Domain` `-cn` `-cp` `-d` corpus 8 (sigma 7, splunk 1) `-sc` corpus 2 (sigma 2) `krbscm` `relay` corpus 2 (sigma 2) `spawn`	`field:"CommandLine" kind:match`
`Image`	ends_with	`\KrbRelayUp.exe`	`field:"Image" kind:ends_with value:"\KrbRelayUp.exe"`
`OriginalFileName`	eq	`KrbRelayUp.exe`	`field:"OriginalFileName" kind:eq value:"KrbRelayUp.exe"`

HackTool - KrbRelayUp Execution

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli_1

Stage 3: selection_cli_2

Stage 4: selection_cli_3

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli_1`

Stage 3: `selection_cli_2`

Stage 4: `selection_cli_3`