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Description

The following analytic detects the creation of suspicious files named passff.tar and cookie.tar, which are indicative of archived stolen browser information such as history and cookies on a machine compromised with IcedID. It leverages Sysmon EventCode 11 to identify these specific filenames. This activity is significant because it suggests that sensitive browser data has been exfiltrated, which could lead to further exploitation or data breaches. If confirmed malicious, this could allow attackers to access personal information, conduct further phishing attacks, or escalate their presence within the network.

  • Type: Hunting

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-18
  • Author: Teoderick Contreras, Splunk
  • ID: 0db4da70-f14b-11eb-8043-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1560.001 Archive via Utility Collection
T1560 Archive Collected Data Collection
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
2
3
4
5



`sysmon` EventCode= 11  (TargetFilename = "*\\passff.tar" OR TargetFilename = "*\\cookie.tar") 
|stats count min(_time) as firstTime max(_time) as lastTime by TargetFilename EventCode process_id  process_name dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `icedid_exfiltrated_archived_file_creation_filter`

Macros

The SPL above uses the following Macros:

:information_source: icedid_exfiltrated_archived_file_creation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • TargetFilename
  • EventCode
  • process_id
  • process_name
  • dest

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
72.0 80 90 Process $process_name$ create a file $TargetFilename$ on host $dest$

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

Reference

Test Dataset

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 | version: 2