Query: alert when Detects an a non-browser process interacting with the Telegram API which could indicate use of a covert C2
Matching passage: Sigma rule: Detects an a non-browser process interacting with the Telegram API which could indicate use of a covert C2. Logsource: windows / network_connection. Rule: title: Suspicious Non-Browser Network Communication With Telegram API id: c3dbbc9f-ef1d-470a-a90a-d343448d5875 status: test description: Detects an a non-browser process interacting with the Telegram API which could indicate use of a covert C2 references: - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/small-sieve/NCSC-MAR-Small-Sieve.pdf author: Nasreddine Bencherchali (Nextron Systems) date: 2023-05-19 tags: - attack.command-and-control - attack.exfiltration - attack.t1102 - attack.t1567 - attack.t1105 logsource: product: windows category: network_connection detection: selection: DestinationHostname|contains: api.telegram.org filter_main_brave: Image|endswith: \brave.exe filter_main_chrome: Image: - C:\Program Files\Google\Chrome\Application\chrome.exe - C:\Program Files (x86)\Google\Chrome\Application\chrome.exe filter_main_firefox: Image: - C:\Program Files\Mozilla Firefox\firefox.exe - C:\Program Files (x86)\Mozilla Firefox\firefox.exe filter_main_ie: Image: - C:\Program Files (x86)\Internet Explorer\iexplore.exe - C:\Program Files\Internet Explorer\iexplore.exe filter_main_maxthon: Image|endswith: \maxthon.exe filter_main_edge_1: - Image|startswith: C:\Program Files (x86)\Microsoft\EdgeWebView\Application\ - Image|endswith: \WindowsApps\MicrosoftEdge.exe - Image: - C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe - C:\Program Files\Microsoft\Edge\Application\msedge.exe filter_main_edge_2: Image|startswith: - C:\Program Files (x86)\Microsoft\EdgeCore\ - C:\Program Files\Microsoft\EdgeCore\ Image|endswith: - \msedge.exe - \msedgewebview2.exe filter_main_opera: Image|endswith: \opera.exe filter_main_safari: Image|endswith: \safari.exe filter_main_seamonkey: Image|endswith: \seamonkey.exe filter_main_vivaldi: Image|endswith: \vivaldi.exe filter_main_whale: Image|endswith: \whale.exe condition: selection and not 1 of filter_main_* falsepositives: - Legitimate applications communicating with the Telegram API e.g. web browsers not in the exclusion list, app with an RSS etc. level: medium
Near-miss passage: Sigma rule: Detects when an attacker adds a new AMSI provider via the Windows Registry to bypass AMSI (Antimalware Scan Interface) p. Logsource: windows / registry_set. Rule: title: Potential Persistence Via New AMSI Providers - Registry id: 33efc23c-6ea2-4503-8cfe-bdf82ce8f705 status: test description: 'Detects when an attacker adds a new AMSI provider via the Windows Registry to bypass AMSI (Antimalware Scan Interface) protections. Attackers may add custom AMSI providers to persist on the system and evade detection by security software that relies on AMSI for scanning scripts and other content. This technique is often used in conjunction with fileless malware and script-based attacks to maintain persistence while avoiding detection. ' references: - https://persistence-info.github.io/Data/amsi.html - https://github.com/gtworek/PSBits/blob/8d767892f3b17eefa4d0668f5d2df78e844f01d8/FakeAMSI/FakeAMSI.c author: Nasreddine Bencherchali (Nextron Systems) date: 2022-07-21 modified: 2025-10-26 tags: - attack.persistence logsource: category: registry_set product: windows detection: selection: TargetObject|contains: - \SOFTWARE\Microsoft\AMSI\Providers\ - \SOFTWARE\WOW6432Node\Microsoft\AMSI\Providers\ filter_optional_avast: Image: - C:\Program Files\Avast Software\Avast\RegSvr.exe - C:\Program Files\Avast Software\Avast\x86\RegSvr.exe TargetObject|contains: \{FB904E4E-D2C7-4C8D-8492-B620BB9896B1} filter_optional_avg: Image: - C:\Program Files\AVG\Antivirus\RegSvr.exe - C:\Program Files\AVG\Antivirus\x86\RegSvr.exe TargetObject|contains: \{FB904E4E-D2C7-4C8D-8492-B620BB9896B1} filter_optional_avira: Image: C:\Program Files\Avira\Endpoint Protection SDK\endpointprotection.exe TargetObject|contains: \{00000001-3DCC-4B48-A82E-E2071FE58E05} condition: selection and not 1 of filter_optional_* falsepositives: - Legitimate security products adding their own AMSI providers. Filter these according to your environment. level: medium regression_tests_path: regression_data/rules/windows/registry/registry_set/registry_set_persistence_amsi_providers/info.yml