OpenSSL contains a vulnerability that could allow an unauthenticated, remote attacker to obtain sensitive information.
The vulnerability is due to improper handling of cryptographic algorithms during the message authentication code (MAC) processing of a ciphertext message. An unauthenticated, remote attacker could exploit the vulnerability by transmitting crafted session initiation packets to a targeted system. A successful attack could allow the attacker to obtain sensitive information used to secure the communication channels.
OpenSSL has confirmed the vulnerability and released software updates.
Indicators of Compromise
OpenSSL versions 1.0.1c and prior, 1.0.0j and prior, and 0.9.8x and prior are vulnerable.
The vulnerability is due to how the CBC cipher suites are used in the SSL, Transport Layer Security (TLS), and Datagram Transport Layer Security (DTLS) protocols. Insufficient cryptographic complexity during the decryption process of MAC in a ciphertext message could allow plaintext recovery timing attacks.
An unauthenticated, remote attacker could exploit the vulnerability by transmitting brute-forced session requests crafted with payload data to a targeted system. While the MAC codes are decrypting, the attacker could use the timing differences to gain knowledge about the message payload.
The vendor report indicates this vulnerability could be partially mitigated when OpenSSL is used in conjunction with the OpenSSL FIPS Object Module and the FIPS mode of operation is enabled.
Administrators are advised to apply the appropriate updates.
Administrators may consider using an alternate product.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
OpenSSL has released a security advisory at the following link: secadv_20130204
Apple has released a security advisory at the following link: HT5880
Oracle customers are advised to acquire the Solaris 9 and 10 updates via normal Oracle support channels.
Red Hat has released updated software for registered subscribers at the following link: Red Hat Network. Red Hat packages can be updated on Red Hat Enterprise Linux versions 5 and later using the yum tool.
Red Hat has released updated packages for registered users at the following links:
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.