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Insecure service configuration - BREACH Attack

Description​

The site meets the conditions that make it potentially vulnerable to BREACH attacks:

  • Uses HTTP gzip compression.
  • The information entered by the user is reflected on the site.
  • It stores secrets (session tokens or anti-CSRF).

Impact​

Allow to obtain privileged information (such as session token) due to the compression features with the gzip format. Additional information can be found at http://breachattack.com/

Recommendation​

Securely configure the vulnerable service so that it can only be accessed by authorized users.

Threat​

Anonymous attacker in adjacent network executing a man-in-the-middle attack.

Expected Remediation Time​

⌚ 30 minutes.

Score​

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base​

  • Attack vector: A
  • Attack complexity: H
  • Privileges required: N
  • User interaction: R
  • Scope: U
  • Confidentiality: L
  • Integrity: N
  • Availability: N

Temporal​

  • Exploit code madurity: U
  • Remediation level: W
  • Report confidence: R

Result​

  • Vector string: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:W/RC:R
  • Score:
    • Base: 2.6
    • Temporal: 2.3
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

There is a secure configuration of the content-encoding header in the http responses

GET HTTP/1.1
Host: hostname
User-Agent: Mozilla/5.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
content-encoding: compress

Non compliant code​

The http responses of the application use the g-zip content-encoding

GET HTTP/1.1
Host: hostname
User-Agent: Mozilla/5.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
content-encoding: gzip

Requirements​

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