CVE-2017-7668

The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value.

The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value.

The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value.

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 issues:

• Allow disabling SNI on proxy connections using 'SetEnv proxy-disable-sni 1' in the configuration files. (bsc#1052830)
• Allow ECDH again in mod_ssl, it had been incorrectly disabled with the 2.2.34 update. (bsc#1064561)

Following security issue has been fixed:

• CVE-2017-9798: A use-after-free in the OPTIONS command could be used by attackers to disclose memory of the apache server process, when htaccess uses incorrect Limit statement. (bsc#1058058)

Additionally, references to the following security issues, fixed by the previous version-update of apache2 to Apache HTTPD 2.2.34 have been added:

• CVE-2017-7668: The HTTP strict parsing introduced a bug in token list parsing, which allowed ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may have be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value. (bsc#1045061)
• CVE-2017-3169: mod_ssl may have de-referenced a NULL pointer when third-party modules call ap_hook_process_connection() during an HTTP request to an HTTPS port allowing for DoS. (bsc#1045062)
• CVE-2017-3167: Use of the ap_get_basic_auth_pw() by third-party modules outside of the authentication phase may have lead to authentication requirements being bypassed. (bsc#1045065)
• CVE-2017-7679: mod_mime could have read one byte past the end of a buffer when sending a malicious Content-Type response header. (bsc#1045060)

Emmanuel Dreyfus discovered that third-party modules using the ap_get_basic_auth_pw() function outside of the authentication phase may lead to authentication requirements being bypassed. This update adds a new ap_get_basic_auth_components() function for use by third-party modules. (CVE-2017-3167)

Vasileios Panopoulos discovered that the Apache mod_ssl module may crash when third-party modules call ap_hook_process_connection() during an HTTP request to an HTTPS port. (CVE-2017-3169)

Javier Jiménez discovered that the Apache HTTP Server incorrectly handled parsing certain requests. A remote attacker could possibly use this issue to cause the Apache HTTP Server to crash, resulting in a denial of service. (CVE-2017-7668)

ChenQin and Hanno Böck discovered that the Apache mod_mime module incorrectly handled certain Content-Type response headers. A remote attacker could possibly use this issue to cause the Apache HTTP Server to crash, resulting in a denial of service. (CVE-2017-7679)