CVE-2018-1283

In Apache httpd 2.4.0 to 2.4.29, when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a "Session" header. This comes from the "HTTP_SESSION" variable name used by mod_session to forward its data to CGIs, since the prefix "HTTP_" is also used by the Apache HTTP Server to pass HTTP header fields, per CGI specifications.

In Apache httpd 2.4.0 to 2.4.29, when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a "Session" header. This comes from the "HTTP_SESSION" variable name used by mod_session to forward its data to CGIs, since the prefix "HTTP_" is also used by the Apache HTTP Server to pass HTTP header fields, per CGI specifications.

In Apache httpd 2.4.0 to 2.4.29, when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a "Session" header. This comes from the "HTTP_SESSION" variable name used by mod_session to forward its data to CGIs, since the prefix "HTTP_" is also used by the Apache HTTP Server to pass HTTP header fields, per CGI specifications.

mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all (CVE-2017-15710).

A regular expression could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. leading to corruption of uploaded files (CVE-2017-15715).

When mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a "Session" header leading to unexpected behavior (CVE-2018-1283).

Due to an out of bound access after a size limit being reached by reading the HTTP header, a specially crafted request could lead to remote denial of service (CVE-2018-1301).

When an HTTP/2 stream was destroyed after being handled, it could have written a NULL pointer potentially to an already freed memory. The memory pools maintained by the server make this vulnerability hard to trigger in usual configurations, the reporter and the team could not reproduce it outside debug builds, so it is classified as low risk (CVE-2018-1302).

A specially crafted HTTP request header could lead to crash due to an out of bound read while preparing data to be cached in shared memory (CVE-2018-1303).

When generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo- random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection (CVE-2018-1312).

Fixed a worker exhaustion that could have lead to a denial of service via specially crafted HTTP/2 requests (CVE-2018-1333).

In Apache HTTP Server by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections (CVE-2018-11763).

The apache package has been updated to version 2.4.37, fixing these issues and several other bugs. See the upstream CHANGES files for details.

This update for apache2 fixes the following issues:

• CVE-2018-1283: when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a 'Session' header leading to unexpected behavior [bsc#1086814].

• CVE-2018-1301: due to an out of bound access after a size limit being reached by reading the HTTP header, a specially crafted request could lead to remote denial of service. [bsc#1086817]

• CVE-2018-1303: a specially crafted HTTP request header could lead to crash due to an out of bound read while preparing data to be cached in shared memory.[bsc#1086813]

• CVE-2017-15715: a regular expression could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. leading to corruption of uploaded files.[bsc#1086774]

• CVE-2018-1312: when generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo-random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection. [bsc#1086775]

• CVE-2017-15710: mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all. [bsc#1086820]

• gensslcert: fall back to 'localhost' as hostname [bsc#1057406]

This update for apache2 fixes the following issues:

• CVE-2018-1283: when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a 'Session' header leading to unexpected behavior [bsc#1086814].

• CVE-2018-1301: due to an out of bound access after a size limit being reached by reading the HTTP header, a specially crafted request could lead to remote denial of service. [bsc#1086817]

• CVE-2018-1303: a specially crafted HTTP request header could lead to crash due to an out of bound read while preparing data to be cached in shared memory.[bsc#1086813]

• CVE-2017-15715: a regular expression could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. leading to corruption of uploaded files.[bsc#1086774]

• CVE-2018-1312: when generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo-random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection. [bsc#1086775]

• CVE-2017-15710: mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all. [bsc#1086820]

• gensslcert: fall back to 'localhost' as hostname [bsc#1057406]

This update for apache2 fixes the following issues:

• CVE-2018-1283: when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a 'Session' header leading to unexpected behavior [bsc#1086814].

• CVE-2018-1301: due to an out of bound access after a size limit being reached by reading the HTTP header, a specially crafted request could lead to remote denial of service. [bsc#1086817]

• CVE-2018-1303: a specially crafted HTTP request header could lead to crash due to an out of bound read while preparing data to be cached in shared memory.[bsc#1086813]

• CVE-2017-15715: a regular expression could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. leading to corruption of uploaded files.[bsc#1086774]

• CVE-2018-1312: when generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo-random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection. [bsc#1086775]

• CVE-2017-15710: mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all. [bsc#1086820]

• CVE-2018-1302: when an HTTP/2 stream was destroyed after being handled, it could have written a NULL pointer potentially to an already freed memory. The memory pools maintained by the server make this vulnerability hard to trigger in usual configurations, the reporter and the team could not reproduce it outside debug builds, so it is classified as low risk. [bsc#1086820]

This update for apache2 fixes the following issues:

• CVE-2018-1283: when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a 'Session' header leading to unexpected behavior [bsc#1086814].

• CVE-2018-1301: due to an out of bound access after a size limit being reached by reading the HTTP header, a specially crafted request could lead to remote denial of service. [bsc#1086817]

• CVE-2018-1303: a specially crafted HTTP request header could lead to crash due to an out of bound read while preparing data to be cached in shared memory.[bsc#1086813]

• CVE-2017-15715: a regular expression could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. leading to corruption of uploaded files.[bsc#1086774]

• CVE-2018-1312: when generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo-random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection. [bsc#1086775]

• CVE-2017-15710: mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all. [bsc#1086820]

• CVE-2018-1302: when an HTTP/2 stream was destroyed after being handled, it could have written a NULL pointer potentially to an already freed memory. The memory pools maintained by the server make this vulnerability hard to trigger in usual configurations, the reporter and the team could not reproduce it outside debug builds, so it is classified as low risk. [bsc#1086820]

Alex Nichols and Jakob Hirsch discovered that the Apache HTTP Server mod_authnz_ldap module incorrectly handled missing charset encoding headers. A remote attacker could possibly use this issue to cause the server to crash, resulting in a denial of service. (CVE-2017-15710)

Elar Lang discovered that the Apache HTTP Server incorrectly handled certain characters specified in <FilesMatch>. A remote attacker could possibly use this issue to upload certain files, contrary to expectations. (CVE-2017-15715)

It was discovered that the Apache HTTP Server mod_session module incorrectly handled certain headers. A remote attacker could possibly use this issue to influence session data. (CVE-2018-1283)

Robert Swiecki discovered that the Apache HTTP Server incorrectly handled certain requests. A remote attacker could possibly use this issue to cause the server to crash, leading to a denial of service. (CVE-2018-1301)

Robert Swiecki discovered that the Apache HTTP Server mod_cache_socache module incorrectly handled certain headers. A remote attacker could possibly use this issue to cause the server to crash, leading to a denial of service. (CVE-2018-1303)

Nicolas Daniels discovered that the Apache HTTP Server incorrectly generated the nonce when creating HTTP Digest authentication challenges. A remote attacker could possibly use this issue to replay HTTP requests across a cluster of servers. (CVE-2018-1312)

USN-3627-1 fixed vulnerabilities in Apache HTTP Server. This update provides the corresponding updates for Ubuntu 18.04 LTS.

Original advisory details:

Alex Nichols and Jakob Hirsch discovered that the Apache HTTP Server mod_authnz_ldap module incorrectly handled missing charset encoding headers. A remote attacker could possibly use this issue to cause the server to crash, resulting in a denial of service. (CVE-2017-15710)

Elar Lang discovered that the Apache HTTP Server incorrectly handled certain characters specified in <FilesMatch>. A remote attacker could possibly use this issue to upload certain files, contrary to expectations. (CVE-2017-15715)

It was discovered that the Apache HTTP Server mod_session module incorrectly handled certain headers. A remote attacker could possibly use this issue to influence session data. (CVE-2018-1283)

Robert Swiecki discovered that the Apache HTTP Server incorrectly handled certain requests. A remote attacker could possibly use this issue to cause the server to crash, leading to a denial of service. (CVE-2018-1301)

Robert Swiecki discovered that the Apache HTTP Server mod_cache_socache module incorrectly handled certain headers. A remote attacker could possibly use this issue to cause the server to crash, leading to a denial of service. (CVE-2018-1303)

Nicolas Daniels discovered that the Apache HTTP Server incorrectly generated the nonce when creating HTTP Digest authentication challenges. A remote attacker could possibly use this issue to replay HTTP requests across a cluster of servers. (CVE-2018-1312)