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Insufficient Verification of Data Authenticity

CVE-2023-48795

Medium
5.9/10

Summary

The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles the use of sequence numbers. For example, there is an effective attack against SSH's use of "ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC)". The bypass occurs in "[email protected]" and (if CBC is used) the "[email protected]" MAC algorithms. This vulnerability affects Go-github.com/golang/crypto package versions prior to 0.17.0, Python-paramiko package versions prior to 3.4.0 and Python-asyncssh package versions prior to 2.14.2, CPP-libssh2 package all verisons, CPP-libssh package versions prior to 0.9.8, and 0.10.x verison prior to 0.10.6, NPM-ssh2 package verisons 1.15.0, Maven-com.github.mwiede:jsch package verisons prior to 0.2.15, Php-phpseclib/phpseclib package version prior to 1.0.22 , 2.0.x prior to 2.0.46 , 3.0.x prior to 3.0.35.

  • HIGH
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • NONE

CWE-345 - Insufficient Verification of Data Authenticity

The software does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

References

Advisory Timeline

  • Published