IC76651: AVOID POTENTIAL ATTACK AGAINST XML ENCRYPTION.

APAR status

• Closed as program error.

Error description

• A vulnerability exists in XML Encryption and other uses of
  CBC-mode encryption, related to the handling of error messages
  issued by or subsequent to decryption.
  

Local fix

• To prevent this attack without installing this APAR, you can:
  
  
  -  Digitally sign the encrypted request message using XML
  Digital Signatures or Message Authentication/Integrity Codes
  (MACs).
  -  Ensure that all responses after encountering an error are
  indistinguishable from each other, which is a simpler approach.
  Providing indistinguishable errors hardens a service against
  this attack with minimal configuration changes.
  
  Please refer to the TechNote on this APAR for specific details
  

Problem summary

• Error messages emitted during or subsequent to decryption
  can reveal cryptographic state.
  

Problem conclusion

• A new property, "rewrite-errors" is added to XML Firewall,
  MPGW and WS-Proxy to control whether errors subsequent to
  decryption are replaced by a generic fault.  By default, this
  property is enabled.
  
  
  The property can be controlled via the WebGUI, on the "XML
  Threat Protection" tab of the configuration screen for each of
  the above services.
  
  This fix is available in 3.7.3.19, 3.8.0.13, 3.8.1.12, 3.8.2.4,
  and 4.0.1.0.
  

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