Detection: Enumerate Users Local Group Using Telegram

Updated Date: 2024-05-15 ID: fcd74532-ae54-11eb-a5ab-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects a Telegram process enumerating all network users in a local group. It leverages EventCode 4798, which is generated when a process enumerates a user's security-enabled local groups on a computer or device. This activity is significant as it may indicate an attempt to gather information on user accounts, a common precursor to further malicious actions. If confirmed malicious, this behavior could allow an attacker to map out user accounts, potentially leading to privilege escalation or lateral movement within the network.

Search

1`wineventlog_security` EventCode=4798  CallerProcessName = "*\\telegram.exe" 
2| stats count min(_time) as firstTime max(_time) as lastTime by user Computer EventCode CallerProcessName  ProcessID SubjectUserSid SubjectDomainName  SubjectLogonId 
3| rename Computer as dest 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `enumerate_users_local_group_using_telegram_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Windows Event Log Security 4798	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`	N/A

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
enumerate_users_local_group_using_telegram_filter	`search *`

enumerate_users_local_group_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
T1087	Account Discovery	Discovery

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

FIN13

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 Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting logs with the Task Schedule (Exa. Security Log EventCode 4798) endpoints. Tune and filter known instances of process like logonUI used in your environment.

Known False Positives

unknown

Associated Analytic Story

XMRig

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
The Telegram application has been identified enumerating local groups on $dest$ by $user$.	80	80	100

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`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: 4