6.8 - RHSA-2016:1140

Problem Description:

An update for squid34 is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64

3. Description:

The "squid34" packages provide version 3.4 of Squid, a high-performance proxy caching server for web clients, supporting FTP, Gopher, and HTTP data objects. Note that apart from "squid34", this version of Red Hat Enterprise Linux also includes the "squid" packages which provide Squid version 3.1.

Security Fix(es):

* A buffer overflow flaw was found in the way the Squid cachemgr.cgi utility processed remotely relayed Squid input. When the CGI interface utility is used, a remote attacker could possibly use this flaw to execute arbitrary code. (CVE-2016-4051)

* Buffer overflow and input validation flaws were found in the way Squid processed ESI responses. If Squid was used as a reverse proxy, or for TLS/HTTPS interception, a remote attacker able to control ESI components on an HTTP server could use these flaws to crash Squid, disclose parts of the stack memory, or possibly execute arbitrary code as the user running Squid. (CVE-2016-4052, CVE-2016-4053, CVE-2016-4054)

* An input validation flaw was found in the way Squid handled intercepted HTTP Request messages. An attacker could use this flaw to bypass the protection against issues related to CVE-2009-0801, and perform cache poisoning attacks on Squid. (CVE-2016-4553)

* An input validation flaw was found in Squid's mime_get_header_field() function, which is used to search for headers within HTTP requests. An attacker could send an HTTP request from the client side with specially crafted header Host header that bypasses same-origin security protections, causing Squid operating as interception or reverse-proxy to contact the wrong origin server. It could also be used for cache poisoning for client not following RFC 7230. (CVE-2016-4554)

* A NULL pointer dereference flaw was found in the way Squid processes ESI responses. If Squid was used as a reverse proxy or for TLS/HTTPS interception, a malicious server could use this flaw to crash the Squid worker process. (CVE-2016-4555)

* An incorrect reference counting flaw was found in the way Squid processes ESI responses. If Squid is configured as reverse-proxy, for TLS/HTTPS interception, an attacker controlling a server accessed by Squid, could crash the squid worker, causing a Denial of Service attack. (CVE-2016-4556)

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.

5. Bugs fixed (https://bugzilla.redhat.com/):

1329126 - CVE-2016-4051 squid: buffer overflow in cachemgr.cgi 1329136 - CVE-2016-4052 CVE-2016-4053 CVE-2016-4054 squid: multiple issues in ESI processing 1334233 - CVE-2016-4553 squid: Cache poisoning issue in HTTP Request handling 1334241 - CVE-2016-4554 squid: Header Smuggling issue in HTTP Request processing 1334246 - CVE-2016-4555 squid: SegFault from ESIInclude::Start 1334786 - CVE-2016-4556 squid: SIGSEGV in ESIContext response handling