Name:Download Files Using Telegram id:58194e28-ae5e-11eb-8912-acde48001122 version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects suspicious file downloads by the Telegram application on a Windows system. It leverages Sysmon EventCode 15 to identify instances where Telegram.exe creates files with a Zone.Identifier, indicating a download. This activity is significant as it may indicate an adversary using Telegram to download malicious tools, such as network scanners, for further exploitation. If confirmed malicious, this behavior could lead to network mapping, lateral movement, and potential compromise of additional systems within the network. Data_source:
-Sysmon EventID 15
search:`sysmon` EventCode= 15 process_name = "telegram.exe" TargetFilename = "*:Zone.Identifier" |stats count min(_time) as firstTime max(_time) as lastTime by dest EventCode process_name process_id TargetFilename Hash | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `download_files_using_telegram_filter`
how_to_implement:To successfully implement this search, you need to be ingesting logs with the process name and TargetFilename from your endpoints or Events that monitor filestream events which is happened when process download something. (EventCode 15) If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. known_false_positives:normal download of file in telegram app. (if it was a common app in network) References: -https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/ drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'XMRig' - 'Phemedrone Stealer' - 'Snake Keylogger' asset_type:Endpoint confidence:70 impact:70 message:Suspicious files were downloaded with the Telegram application on $dest$ mitre_attack_id: - 'T1105' observable: name:'dest' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'dest' - 'EventCode' - 'Image' - 'process_id' - 'TargetFilename' - 'Hash' risk_score:49 security_domain:endpoint
