CVE-2016-0736

In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto 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.

In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto 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.

mod_sessioncrypto 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 (CVE-2016-0736).

Malicious input to mod_auth_digest will cause the server to crash, and each instance continues to crash even for subsequently valid requests (CVE-2016-2161).

Emmanuel Dreyfus reported that the use of ap_get_basic_auth_pw() by third-party modules outside of the authentication phase may lead to authentication requirements being bypassed (CVE-2017-3167).

Vasileios Panopoulos of AdNovum Informatik AG discovered that mod_ssl may dereference a NULL pointer when third-party modules call ap_hook_process_connection() during an HTTP request to an HTTPS port leading to a denial of service (CVE-2017-3169).

Javier Jimenez reported that the HTTP strict parsing contains a flaw leading to a buffer overread in ap_find_token(). A remote attacker can take advantage of this flaw by carefully crafting a sequence of request headers to cause a segmentation fault, or to force ap_find_token() to return an incorrect value (CVE-2017-7668).

ChenQin and Hanno Boeck reported that mod_mime can read one byte past the end of a buffer when sending a malicious Content-Type response header (CVE-2017-7679).

Robert Swiecki reported that mod_auth_digest does not properly initialize or reset the value placeholder in [Proxy-]Authorization headers of type "Digest" between successive key=value assignments, leading to information disclosure or denial of service (CVE-2017-9788).

Hanno Böck discovered that the Apache HTTP Server incorrectly handled Limit directives in .htaccess files. In certain configurations, a remote attacker could possibly use this issue to read arbitrary server memory, including sensitive information. This issue is known as Optionsbleed (CVE-2017-9798).

This update for apache2 fixes the following security issues:

Security issues fixed:

• CVE-2016-0736: Protect mod_session_crypto data with a MAC to prevent padding oracle attacks (bsc#1016712).
• CVE-2016-2161: Malicious input to mod_auth_digest could have caused the server to crash, resulting in DoS (bsc#1016714).
• CVE-2016-8743: Added new directive 'HttpProtocolOptions Strict' to avoid proxy chain misinterpretation (bsc#1016715).

Bugfixes:

• Add missing copy of hcuri and hcexpr from the worker to the health check worker (bsc#1019380).

This update for apache2 provides the following fixes:

Security issues fixed:

• CVE-2016-0736: Protect mod_session_crypto data with a MAC to prevent padding oracle attacks (bsc#1016712).
• CVE-2016-2161: Malicious input to mod_auth_digest could have caused the server to crash, resulting in DoS (bsc#1016714).
• CVE-2016-8743: Added new directive 'HttpProtocolOptions Strict' to avoid proxy chain misinterpretation (bsc#1016715).

Bugfixes:

• Add NotifyAccess=all to systemd service files to prevent warnings in the log when using mod_systemd (bsc#980663).

It was discovered that the Apache mod_session_crypto module was encrypting data and cookies using either CBC or ECB modes. A remote attacker could possibly use this issue to perform padding oracle attacks. (CVE-2016-0736)

Maksim Malyutin discovered that the Apache mod_auth_digest module incorrectly handled malicious input. A remote attacker could possibly use this issue to cause Apache to crash, resulting in a denial of service. (CVE-2016-2161)

David Dennerline and Régis Leroy discovered that the Apache HTTP Server incorrectly handled unusual whitespace when parsing requests, contrary to specifications. When being used in combination with a proxy or backend server, a remote attacker could possibly use this issue to perform an injection attack and pollute cache. This update may introduce compatibility issues with clients that do not strictly follow HTTP protocol specifications. A new configuration option "HttpProtocolOptions Unsafe" can be used to revert to the previous unsafe behaviour in problematic environments. (CVE-2016-8743)