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Insecure encryption algorithm - Perfect Forward Secrecy

Description​

The application uses cipher algorithms that expose all messages made during the communication if the current private key is compromised.

Impact​

Obtain sensitive information that is being transmitted or has been stored.

Recommendation​

Enable Perfect-Forward-Secrecy in the server side, by allowing Ciphersuites that contain DHE and ECDHE on its names.

Threat​

Unauthorized attacker from adjacent network that has compromised a private key.

Expected Remediation Time​

⌚ 15 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: P
  • Remediation level: O
  • Report confidence: X

Result​

  • Vector string: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:X
  • Score:
    • Base: 2.6
    • Temporal: 2.4
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

The application only includes secure encryption algorithms

http {
  server {
    index index.html;
    listen localhost:4446 ssl;
    location / {
      root server_root;
    }
    server_name localhost;
    ssl_prefer_server_ciphers off;
    ssl_ciphers "EECDH+AESGCM:EDH+AESGCM";
    ssl_certificate ert.crt;
    ssl_certificate_key cert.key;
    ssl_protocols SSLv3 TLSv1 TLSv1.2;
  }
}

Non compliant code​

Some insecure encryption algorithms are included in the server configuration

http {
  server {
    index index.html;
    listen localhost:4446 ssl;
    location / {
      root server_root;
    }
    server_name localhost;
    ssl_prefer_server_ciphers off;
    ssl_ciphers "ADH-AES128-SHA:ADH-AES256-SHA:ADH-CAMELLIA128-SHA:ADH-CAMELLIA256-SHA:ADH-DES-CBC3-SHA:ADH-RC4-MD5:ADH-SEED-SHA:AES128-SHA:AES256-SHA:CAMELLIA128-SHA:ADH-SEED-SHA:AES128-SHA";
    ssl_certificate ert.crt;
    ssl_certificate_key cert.key;
    ssl_protocols SSLv3 TLSv1 TLSv1.1;
  }
}

Requirements​

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