IC90431: "LUCKY 13" PLAINTEXT RECOVERY ATTACK AGAINST SSL/TLS WITH CBC CIPHERS (CVE-2013-0169)

APAR status

• Closed as program error.

Error description

• A security vulnerability was discovered in SSL and TLS
  protocols when CBC ciphers are used (such as 3DES and AES in CBC
  mode).  Small differences in the time taken during MAC
  processing can leak enough information to allow  a
  man-in-the-middle attacker to recover plaintext information from
  previous SSL/TLS connections.
  
  This vulnerability is known as CVE-2013-0169 and also as "Lucky
  13".
  
  The DataPower appliance's SSL implementation is vulnerable to
  this attack when CBC cipher suites are used (but not when stream
  cipher suites are used).
  
  
  The protocol problem that allows the attack only affects block
  ciphers such as 3DES and AES.  There is one stream cipher
  supported by SSL/TLS called RC4.  Using a stream cipher avoids
  this attack entirely.
  

Local fix

• Use a stream cipher (RC4) to alleviate this vulnerability until
  the APAR fix is available.
  
  
  
  To configure this in the DataPower WebGUI, enter the string
  RC4-SHA:RC4-MD5 into the Ciphers property in the Crypto Profile
  and Save. With this configuration setting, DataPower
  negotiates strong, non-export cipher suites involving RC4 - a
  stream cipher rather than a block cipher.
  

Problem summary

• Customers using the DataPower SSL stack with CBC cipher suites
  (3DES or AES) are vulnerable to the "Lucky 13" attack
  (CVE-2013-0169).
  

Problem conclusion

• The fix is available in 4.0.1.17, 4.0.2.13, and 5.0.0.8.
  
  For a list of the latest fix packs available, please see:
  http://www-01.ibm.com/support/docview.wss?uid=swg21237631
  

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

• R401 PSY

     UP

• R402 PSY

     UP

• R500 PSY

     UP

• R382 PSN

     UP