:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

Try in Splunk Security Cloud

Description

This search looks for unusually long strings in the Content-Type http header that the client sends the server.

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

  • Last Updated: 2017-10-13
  • Author: Bhavin Patel, Splunk
  • ID: 57a0a2bf-353f-40c1-84dc-29293f3c35b7

Annotations

ATT&CK
Kill Chain Phase
  • Delivery
NIST
  • ID.RA
  • RS.MI
  • PR.PT
  • PR.IP
  • DE.AE
  • PR.MA
  • DE.CM
CIS20
  • CIS 3
  • CIS 4
  • CIS 18
  • CIS 12
CVE
1
2
3
4
5
`stream_http` 
| eval cs_content_type_length = len(cs_content_type) 
| where cs_content_type_length > 100 
| table endtime src_ip dest_ip cs_content_type_length cs_content_type url 
| `unusually_long_content_type_length_filter`

Macros

The SPL above uses the following Macros:

:information_source: unusually_long_content-type_length_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
  • cs_content_type
  • endtime
  • src_ip
  • dest_ip
  • url

How To Implement

This particular search leverages data extracted from Stream:HTTP. You must configure the http stream using the Splunk Stream App on your Splunk Stream deployment server to extract the cs_content_type field.

Known False Positives

Very few legitimate Content-Type fields will have a length greater than 100 characters.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

: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

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