DISPUTED The modphp module for the Apache HTTP Server allows local users with write access to PHP scripts to send signals to the server's process group and use the server's file descriptors, as demonstrated by sending a STOP signal, then intercepting incoming connections on the server's TCP port. NOTE: the PHP developer has disputed this vulnerability, saying "The opened file descriptors are opened by Apache. It is the job of Apache to protect them ... Not a bug in PHP."

Multiple stack-based buffer overflows in (1) modalias and (2) modrewrite for Apache before 1.3.29 allow attackers to create configuration files to cause a denial of service (crash) or execute arbitrary code via a regular expression with more than 9 captures.

The prefork MPM in Apache 2 before 2.0.47 does not properly handle certain errors from accept, which could lead to a denial of service.

Apache 2 before 2.0.47, when running on an IPv6 host, allows attackers to cause a denial of service (CPU consumption by infinite loop) when the FTP proxy server fails to create an IPv6 socket.

Apache 2 before 2.0.47, and certain versions of modssl for Apache 1.3, do not properly handle "certain sequences of per-directory renegotiations and the SSLCipherSuite directive being used to upgrade from a weak ciphersuite to a strong one," which could cause Apache to use the weak ciphersuite.

Unknown vulnerability in filestat.c for Apache running on OS2, versions 2.0 through 2.0.45, allows unknown attackers to cause a denial of service via requests related to device names.

Apache 2.0 before 2.0.44 on Windows platforms allows remote attackers to obtain certain files via an HTTP request that ends in certain illegal characters such as ">", which causes a different filename to be processed and served.

Apache before 2.0.44, when running on unpatched Windows 9x and Me operating systems, allows remote attackers to cause a denial of service or execute arbitrary code via an HTTP request containing MS-DOS device names.

Format string vulnerability in the modtcl module 1.0 for Apache 2.x allows context-dependent attackers to execute arbitrary code via format string specifiers that are not properly handled in a setvar function call in (1) tclcmds.c and (2) tclcore.c.

modules/arch/win32/modisapi.c in modisapi in the Apache HTTP Server 2.0.37 through 2.0.63, 2.2.0 through 2.2.14, and 2.3.x before 2.3.7, when running on Windows, does not ensure that request processing is complete before calling isapiunload for an ISAPI .dll module, which allows remote attackers to execute arbitrary code via unspecified vectors related to a crafted request, a reset packet, and "orphaned callback pointers."

Cross-site scripting (XSS) vulnerability in modautoindex.c in the Apache HTTP Server before 2.2.6, when the charset on a server-generated page is not defined, allows remote attackers to inject arbitrary web script or HTML via the P parameter using the UTF-7 charset. NOTE: it could be argued that this issue is due to a design limitation of browsers that attempt to perform automatic content type detection.

moddav in Apache before 2.0.42 does not properly handle versioning hooks, which may allow remote attackers to kill a child process via a null dereference and cause a denial of service (CPU consumption) in a preforked multi-processing module.

Cross-site scripting (XSS) vulnerability in the default error page of Apache 2.0 before 2.0.43, and 1.3.x up to 1.3.26, when UseCanonicalName is "Off" and support for wildcard DNS is present, allows remote attackers to execute script as other web page visitors via the Host: header, a different vulnerability than CAN-2002-1157.

Directory traversal vulnerability in Apache 2.0 through 2.0.39 on Windows, OS2, and Netware allows remote attackers to read arbitrary files and execute commands via .. (dot dot) sequences containing \ (backslash) characters.

Apache 2.0 through 2.0.39 on Windows, OS2, and Netware allows remote attackers to determine the full pathname of the server via (1) a request for a .var file, which leaks the pathname in the resulting error message, or (2) via an error message that occurs when a script (child process) cannot be invoked.

Apache 1.3 through 1.3.24, and Apache 2.0 through 2.0.36, allows remote attackers to cause a denial of service and possibly execute arbitrary code via a chunk-encoded HTTP request that causes Apache to use an incorrect size.

moddiskcache in Apache 2.0 through 2.0.49 stores client headers, including authentication information, on the hard disk, which could allow local users to gain sensitive information.

The modssl module in Apache 2.0.35 through 2.0.52, when using the "SSLCipherSuite" directive in directory or location context, allows remote clients to bypass intended restrictions by using any cipher suite that is allowed by the virtual host configuration.

Memory leak in sslengineio.c for modssl in Apache 2 before 2.0.49 allows remote attackers to cause a denial of service (memory consumption) via plain HTTP requests to the SSL port of an SSL-enabled server.

PHP 4.3.4 and earlier in Apache 1.x and 2.x (modphp) can leak global variables between virtual hosts that are handled by the same Apache child process but have different settings, which could allow remote attackers to obtain sensitive information.

Cross-site scripting (XSS) vulnerability in the modimap module of Apache httpd before 1.3.35-dev and Apache httpd 2.0.x before 2.0.56-dev allows remote attackers to inject arbitrary web script or HTML via the Referer when using image maps.

modssl in Apache 2.0 up to 2.0.55, when configured with an SSL vhost with access control and a custom error 400 error page, allows remote attackers to cause a denial of service (application crash) via a non-SSL request to an SSL port, which triggers a NULL pointer dereference.

Memory leak in the worker MPM (worker.c) for Apache 2, in certain circumstances, allows remote attackers to cause a denial of service (memory consumption) via aborted connections, which prevents the memory for the transaction pool from being reused for other connections.

The byte-range filter in Apache 2.0 before 2.0.54 allows remote attackers to cause a denial of service (memory consumption) via an HTTP header with a large Range field.

An Uncontrolled Resource Consumption vulnerability in multiple products may allow an attacker to cause web service portal denial of service (DoS) via handling special crafted HTTP requests/responses in pieces slowly. Slow HTTP attacks are denial-of-service (DoS) attacks in which the attacker sends HTTP requests in pieces slowly, one at a time to a Web server. If an HTTP request is not complete, or if the transfer rate is very low, the server keeps its resources busy waiting for the rest of the data. When the server’s concurrent connection pool reaches its maximum, this creates a DoS. Slow HTTP attacks are easy to execute because they require only minimal resources from the attacker.

Cross-site scripting (XSS) vulnerability in modstatus in the Apache HTTP Server 2.2.0 through 2.2.6, 2.0.35 through 2.0.61, and 1.3.2 through 1.3.39, when the server-status page is enabled, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Martin Joey Schulze discovered a flaw in the way modauthmysql handles certain multibyte character encodings.

If modauthmysql is configured to use use a multibyte character set that allows the backslash '\' character as part of the character encodings, it is possible to inject arbitrary SQL commands to the MySQL database server.

Cross-site scripting (XSS) vulnerability in Apache 2.2.6 and earlier allows remote attackers to inject arbitrary web script or HTML via UTF-7 encoded URLs that are not properly handled when displaying the 403 Forbidden error page.

It was reported [1] that an integer overflow was found in Apache in the appregsub() function called from mod-setenvif. When a header field is mangled using SetEnvIf, the new environment variable data can be multiples of the size of the submitted header field. This would cause appregsub() to overflow the length value in buffer size calculations, leading to the subsequent allocation call of a too-small buffer. Filling this buffer with user-supplied data will lead to a buffer overflow.

Depending on the input data, this can lead to excessive allocation of server memory (resulting in killed processes due to out-of-memory conditions), invalid memory access when copying large amounts of data (which can lead to a termination of the httpd process), or possibly allowing the execution of arbitrary code.

To trigger this flaw, modsetenvif must be enabled (the default) and the attacker needs to be able to place a crafted .htaccess file on the server (which, in most cases, would require local access to the file system or some web interface that allows for writing arbitrary files to the local file system, such as for custom .htaccess files).

There is currently no upstream fix, however to work around the problem, disable modsetenvif.

[1] http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/

Additional problems were discovered in the httpd fix for CVE-2011-3368 - a reverse proxy bypass flaw - tracked via bug #740045. Upstream mailing list post identifies following request forms, which are not handled correctly:

GET @localhost::8880 HTTP/1.0\r\n\r\n GET qualys:@qqq.qq.qualys.com HTTP/1.0\r\n\r\n

Reference: http://thread.gmane.org/gmane.comp.apache.devel/46440