CodeQL documentation

Use of insecure SSL/TLS version

ID: py/insecure-protocol
Kind: problem
Severity: warning
Precision: high
Tags:
   - security
   - external/cwe/cwe-327
Query suites:
   - python-code-scanning.qls
   - python-security-extended.qls
   - python-security-and-quality.qls

Click to see the query in the CodeQL repository

Using a broken or weak cryptographic protocol may make a connection vulnerable to interference from an attacker.

Recommendation

Ensure that a modern, strong protocol is used. All versions of SSL, and TLS 1.0 are known to be vulnerable to attacks. Using TLS 1.1 or above is strongly recommended.

Example

The following code shows a variety of ways of setting up a connection using SSL or TLS. They are all insecure because of the version specified.

import ssl
import socket

# Using the deprecated ssl.wrap_socket method
ssl.wrap_socket(socket.socket(), ssl_version=ssl.PROTOCOL_SSLv2)

# Using SSLContext
context = ssl.SSLContext(ssl_version=ssl.PROTOCOL_SSLv3)

# Using pyOpenSSL

from pyOpenSSL import SSL

context = SSL.Context(SSL.TLSv1_METHOD)


All cases should be updated to use a secure protocol, such as PROTOCOL_TLSv1_1.

Note that ssl.wrap_socket has been deprecated in Python 3.7. A preferred alternative is to use ssl.SSLContext, which is supported in Python 2.7.9 and 3.2 and later versions.

References