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Atomicorp WAF Rule 340362

Rule Summary

  • Rule ID: 340362
  • Status: Active
  • Alert message: Atomicorp.com WAF Rules: ModSecurity does not support content encodings and can not detect attacks using it, therefore it must be blocked.
  • Observed CWEs: None documented
  • Revision: 3
  • Rule severity: Error (3)
  • Phase: 1 (request headers)
  • Request surfaces: Request headers
  • Rule action: deny
  • HTTP status: 501
  • Logging: log, auditlog

Description

Inbound undefined compressed content (not be confused with compressed files or properly defined compressed content) is invisible to all Web Application Firewalls. Therefore they can not see or evaluate any traffic encoded in this manner. If an attack were to be encoded in this way the WAF would not catch it, therefore WAFs are configured to block this traffic.

This rule looks for this header:

Content-Encoding: Identity

If this header exists, the request is rejected because the WAF can not decode this kind of content. It is invisible to the WAF (because its compressed, but the method of compression is not defined, so the WAF has no idea how to uncompress it), and therefore an attack can simply bypass the WAF by compressing an attack.

This is a selected list of documented research observations, not an exhaustive coverage matrix. Absence of a CVE does not imply absence of protection.

No selected related public CVE research notes are currently published.

Documentation Source

  • Original wiki page: WAF 340362
  • Source revision: 3534
  • Source revision date: 2013-06-15