IC74203: CIPHERSUITE DOWNGRADE ATTACK AGAINST SSL SERVER WITH SESSION CACHING ENABLED

APAR status

• Closed as program error.

Error description

• When a DataPower service acts as an SSL server with server side
  session caching
  enabled it is possible for a malicious client to modify the
  ciphersuite
  associated with a saved session in that SSL server's session
  cache.
  
  The malicious client can only change the associated ciphersuite
  to a value
  that the SSL server would support on the initial handshake which
  limits
  the severity of this attack.  The attacker cannot associate a
  weak cipher
  with the session if the server does not support weak ciphers in
  the initial
  handshake.  By default the DataPower SSL server does not support
  weak
  ciphers in the initial handshake.
  

Local fix

• Yes.  Disabling Server-side Session Caching in a given SSL Proxy
  Profile
  object will avoid the problem for all subsequent SSL connections
  to services
  using that object.
  

Problem summary

• Fix the ciphersuite downgrade attack.
  

Problem conclusion

• The fix is available in 3.7.3.17, 3.8.0.11, 3.8.1.10 and
  3.8.2.2.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DATAPOWER

• Fixed component ID

  DP1234567

Applicable component levels

• R373 PSY

     UP

• R380 PSY

     UP

• R381 PSY

     UP

• R382 PSY

     UP