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Detection rules › Sigma

Suspicious Download From Direct IP Via Bitsadmin

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

Detects usage of bitsadmin downloading a file using an URL that contains an IP

MITRE ATT&CK coverage

TacticTechniques
Execution
Persistence
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Suspicious Download From Direct IP Via Bitsadmin
id: 99c840f2-2012-46fd-9141-c761987550ef
related:
    - id: 90f138c1-f578-4ac3-8c49-eecfd847c8b7
      type: similar
status: test
description: Detects usage of bitsadmin downloading a file using an URL that contains an IP
references:
    - https://blog.netspi.com/15-ways-to-download-a-file/#bitsadmin
    - https://isc.sans.edu/diary/22264
    - https://lolbas-project.github.io/lolbas/Binaries/Bitsadmin/
    - https://blog.talosintelligence.com/breaking-the-silence-recent-truebot-activity/
author: Florian Roth (Nextron Systems)
date: 2022-06-28
modified: 2023-02-15
tags:
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1197
    - attack.s0190
    - attack.t1036.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\bitsadmin.exe'
        - OriginalFileName: 'bitsadmin.exe'
    selection_flags:
        CommandLine|contains:
            - ' /transfer '
            - ' /create '
            - ' /addfile '
    selection_extension:
        CommandLine|contains:
            - '://1'
            - '://2'
            - '://3'
            - '://4'
            - '://5'
            - '://6'
            - '://7'
            - '://8'
            - '://9'
    filter_seven_zip:
        CommandLine|contains: '://7-' # For https://7-zip.org/
    condition: all of selection_* and not 1 of filter_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_bitsadmin_download_direct_ip/info.yml

Stages and Predicates

Stage 0: condition

all of selection_* and not 1 of filter_*

Stage 1: selection_img

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

Stage 2: selection_flags

selection_flags:
    CommandLine|contains:
        - ' /transfer '
        - ' /create '
        - ' /addfile '

Stage 3: selection_extension

selection_extension:
    CommandLine|contains:
        - '://1'
        - '://2'
        - '://3'
        - '://4'
        - '://5'
        - '://6'
        - '://7'
        - '://8'
        - '://9'

Stage 4: not filter_seven_zip

filter_seven_zip:
    CommandLine|contains: '://7-'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
CommandLinematch://7-excludes:CommandLine field:"CommandLine" value:"://7-"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • /addfile corpus 5 (sigma 5)
  • /create corpus 15 (sigma 15)
  • /transfer corpus 5 (sigma 5)
  • ://1 corpus 3 (sigma 3)
  • ://2 corpus 3 (sigma 3)
  • ://3 corpus 3 (sigma 3)
  • ://4 corpus 3 (sigma 3)
  • ://5 corpus 3 (sigma 3)
  • ://6 corpus 3 (sigma 3)
  • ://7 corpus 3 (sigma 3)
  • ://8 corpus 3 (sigma 3)
  • ://9 corpus 3 (sigma 3)
field:"CommandLine" kind:match
Imageends_with
  • \bitsadmin.exe corpus 29 (sigma 29)
field:"Image" kind:ends_with value:"\bitsadmin.exe"
OriginalFileNameeq
  • bitsadmin.exe corpus 20 (sigma 9, elastic 8, splunk 2, kusto 1)
field:"OriginalFileName" kind:eq value:"bitsadmin.exe"