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Description

The following analytic identifies potential exploit attempts involving command and script interpreters blocked by Zscaler. It leverages web proxy logs to detect incidents where actions are blocked due to exploit references. The detection compiles statistics by user, threat name, URL, hostname, file class, and filename. This activity is significant as it helps identify and mitigate exploit attempts, which are critical for maintaining security. If confirmed malicious, such activity could lead to unauthorized code execution, privilege escalation, or persistent access within the environment, posing a severe threat to organizational security.

  • Type: TTP

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

  • Last Updated: 2024-05-13
  • Author: Rod Soto, Gowthamaraj Rajendran, Splunk
  • ID: 94665d8c-b841-4ff4-acb4-34d613e2cbfe

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1566 Phishing Initial Access
Kill Chain Phase
  • Delivery
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


1
2
3
4
5



`zscaler_proxy` action=blocked threatname=*exploit* 
| stats count min(_time) as firstTime max(_time) as lastTime  by user threatname src hostname fileclass filename url dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `zscaler_exploit_threat_blocked_filter`

Macros

The SPL above uses the following Macros:

:information_source: zscaler_exploit_threat_blocked_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.

  • action
  • threatname
  • deviceowner
  • user
  • urlcategory
  • url
  • dest
  • dest_ip
  • action

How To Implement

You must install the latest version of Zscaler Add-on from Splunkbase. You must be ingesting Zscaler events into your Splunk environment through an ingester. This analytic was written to be used with the "zscalernss-web" sourcetype leveraging the Zscaler proxy data. This enables the integration with Splunk Enterprise Security. Security teams are encouraged to adjust the detection parameters, ensuring the detection is tailored to their specific environment.

Known False Positives

False positives are limited to Zscaler configuration.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
40.0 50 80 Potential Exploit Threat from dest -[$dest$] on $src$ for user-[$user$].

: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