Unsigned BITS Service Client Process

[metadata]
creation_date = "2023/09/27"
integration = ["endpoint"]
maturity = "production"
updated_date = "2024/05/21"

[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
Identifies an unsigned Windows Background Intelligent Transfer Service (BITS) client process. Attackers may abuse BITS
functionality to download or upload data using the BITS service.
"""
from = "now-119m"
index = ["logs-endpoint.events.library-*"]
interval = "60m"
language = "eql"
license = "Elastic License v2"
name = "Unsigned BITS Service Client Process"
references = [
    "https://web.archive.org/web/20230531215706/https://blog.menasec.net/2021/05/hunting-for-suspicious-usage-of.html",
    "https://www.elastic.co/blog/hunting-for-persistence-using-elastic-security-part-2",
]
risk_score = 21
rule_id = "9a3884d0-282d-45ea-86ce-b9c81100f026"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Defense Evasion",
    "Rule Type: BBR",
    "Data Source: Elastic Defend",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
library where dll.name : "Bitsproxy.dll" and process.executable != null and
not process.code_signature.trusted == true and
not process.code_signature.status : ("errorExpired", "errorCode_endpoint*")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1036"
name = "Masquerading"
reference = "https://attack.mitre.org/techniques/T1036/"
[[rule.threat.technique.subtechnique]]
id = "T1036.001"
name = "Invalid Code Signature"
reference = "https://attack.mitre.org/techniques/T1036/001/"


[[rule.threat.technique]]
id = "T1197"
name = "BITS Jobs"
reference = "https://attack.mitre.org/techniques/T1197/"


[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"