Detection: Download Files Using Telegram

Updated Date: 2026-05-13 ID: 58194e28-ae5e-11eb-8912-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

 1`sysmon` EventCode= 15 process_name = "telegram.exe" TargetFilename = "*:Zone.Identifier"
 2  
 3| stats count min(_time) as firstTime max(_time) as lastTime
 4    BY dest dvc file_hash
 5       file_name file_path process_exec
 6       process_guid process_id process_name
 7       process_path signature signature_id
 8       user_id vendor_product Contents
 9       Image
10  
11| `security_content_ctime(firstTime)`
12  
13| `security_content_ctime(lastTime)`
14  
15| `download_files_using_telegram_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 15	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
sysmon	`(source=WinEventLog:Microsoft-Windows-Sysmon/Operational OR source=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational OR source=Syslog:Linux-Sysmon/Operational)`
download_files_using_telegram_filter	`search *`

download_files_using_telegram_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1105	Ingress Tool Transfer	Command and Control

Command and Control

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

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)

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
Suspicious files were downloaded with the Telegram application on $dest$	dest	system	50

References

https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 12