Telegram API Access — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2018-06-05 / 2023-05-18.

{
  "category": "proxy"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 821e65a82caccce507aacc6e736de44294abbac2e83b513318da0749d06af205

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Telegram API Access
id: b494b165-6634-483d-8c47-2026a6c52372
status: test
description: Detects suspicious requests to Telegram API without the usual Telegram User-Agent
references:
    - https://researchcenter.paloaltonetworks.com/2018/03/unit42-telerat-another-android-trojan-leveraging-telegrams-bot-api-to-target-iranian-users/
    - https://blog.malwarebytes.com/threat-analysis/2016/11/telecrypt-the-ransomware-abusing-telegram-api-defeated/
    - https://www.welivesecurity.com/2016/12/13/rise-telebots-analyzing-disruptive-killdisk-attacks/
author: Florian Roth (Nextron Systems)
date: 2018-06-05
modified: 2023-05-18
tags:
    - attack.command-and-control
    - attack.t1071.001
    - attack.t1102.002
logsource:
    category: proxy
detection:
    selection:
        cs-host: 'api.telegram.org' # Often used by Bots
    filter:
        c-useragent|contains:
            # Used https://core.telegram.org/bots/samples for this list
            - 'Telegram'
            - 'Bot'
    condition: selection and not filter
falsepositives:
    - Legitimate use of Telegram bots in the company
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate use of Telegram bots in the company

Source references

• https://researchcenter.paloaltonetworks.com/2018/03/unit42-telerat-another-android-trojan-leveraging-telegrams-bot-api-to-target-iranian-users/
• https://blog.malwarebytes.com/threat-analysis/2016/11/telecrypt-the-ransomware-abusing-telegram-api-defeated/
• https://www.welivesecurity.com/2016/12/13/rise-telebots-analyzing-disruptive-killdisk-attacks/