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Sid 1-42133

Message

SERVER-APACHE Apache modsessioncrypto padding oracle brute force attempt

Summary

In Apache HTTP Server versions 2.4.0 to 2.4.23, modsessioncrypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.

Impact

CVSS base score 7.5 CVSS impact score 3.6 CVSS exploitability score 3.9 confidentialityImpact HIGH integrityImpact NONE availabilityImpact NONE

CVE-2016-0736:

CVSS base score 7.5

CVSS impact score 3.6

CVSS exploitability score 3.9

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Detailed information

CVE-2016-0736: In Apache HTTP Server versions 2.4.0 to 2.4.23, modsessioncrypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.

Affected systems

  • apache http_server 2.4.0
  • apache http_server 2.4.1
  • apache http_server 2.4.2
  • apache http_server 2.4.3
  • apache http_server 2.4.6
  • apache http_server 2.4.7
  • apache http_server 2.4.8
  • apache http_server 2.4.9
  • apache http_server 2.4.10
  • apache http_server 2.4.12
  • apache http_server 2.4.14
  • apache http_server 2.4.16
  • apache http_server 2.4.19
  • apache http_server 2.4.20
  • apache http_server 2.4.21
  • apache http_server 2.4.22
  • apache http_server 2.4.23

Ease of attack

CVE-2016-0736:

Access Vector

Access Complexity

Authentication

False positives

None known

False negatives

None known

Corrective action

Upgrade to the latest non-affected version of the software.

Apply the appropriate vendor supplied patches.

Contributors

  • Talos research team.
  • This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology.
  • For more information see nvd.

Additional References

  • httpd.apache.org/security/vulnerabilities_24.html