Detection rules › YARA-L

sap sensitive rfc function module execution

Severity
high
Time window
1h
Match by
function_module, user
Author
Google Cloud Security
Source
github.com/chronicle/detection-rules

Detects the execution of sensitive function modules via RFC (AUK). Targets Parameter 3 for the function module name.

MITRE ATT&CK coverage

TacticTechniques
Execution

Rule body

// Copyright 2026 Google LLC. Licensed under Apache-2.0.

rule sap_sensitive_rfc_function_module_execution {

  meta:
    author = "Google Cloud Security"
    description = "Detects the execution of sensitive function modules via RFC (AUK). Targets Parameter 3 for the function module name."
    severity = "High"
    tactic = "TA0002"
    technique = "T1129"

  events:
    $e.metadata.log_type = "SAP_SECURITY_AUDIT"

    $e.additional.fields["msg_1"] = "AUK"
    $e.additional.fields["param3_1"] in %sap_sensitive_function_modules.module

    $function_module = $e.additional.fields["param3_1"]
    $user = $e.principal.user.userid

    not $user in %sap_admin_users.user

  match:
    $user, $function_module over 1h

  outcome:
    $risk_score = 75
    $target_sid = array_distinct($e.target.application)
    $function_group = array_distinct($e.additional.fields["param1_1"])
    $description = array_distinct($e.metadata.description)
    $t_code = array_distinct($e.security_result.detection_fields["slgtc_1"])

  condition:
    $e
}

YARA-L rule structure

Condition

Fires when at least one $e event in the 1h window.

Events

$e

  • metadata.log_type = "SAP_SECURITY_AUDIT"
  • additional.fields["msg_1"] = "AUK"
  • additional.fields["param3_1"] in "%sap_sensitive_function_modules.module"
  • principal.user.userid in "%sap_admin_users.user"

Match and correlation

Match key
$function_module, $user
Within
1h

Outcome

Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.

FieldExpression
risk_score75
target_sidarray_distinct($e.target.application)
function_grouparray_distinct($e.additional.fields["param1_1"])
descriptionarray_distinct($e.metadata.description)
t_codearray_distinct($e.security_result.detection_fields["slgtc_1"])