__________________________________________________________________

  Squid Proxy Cache Security Update Advisory SQUID-2020:13
__________________________________________________________________

Advisory ID:       | SQUID-2020:13
Date:              | September 06, 2023
Summary:           | Denial of Service in gopher gateway
Affected versions: | Squid 2.x -> 2.7.STABLE9
                   | Squid 3.x -> 3.5.28
                   | Squid 4.x -> 4.14
                   | Squid 5.x -> 5.6
Fixed in version:  | Squid 6.0.1
__________________________________________________________________

Problem Description:

 Due to a buffer overflow bug Squid is vulnerable to a Denial of Service
 attack against Squid's gopher gateway.

__________________________________________________________________

Severity:

 This problem allows a remote gopher: server to trigger a buffer
 overflow by delivering large gopher protocol responses.
 On most operating systems with memory protection this will
 halt Squid service immediately, causing a denial of service to
 all Squid clients.

 The gopher protocol is always available and enabled in Squid
 prior to Squid 6.0.1

 Responses triggering this bug are possible to be received from
 any gopher server, even those without malicious intent.


CVSS Score of 7.5
<https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H&version=3.1>

__________________________________________________________________

Updated Packages:

 The gopher support has been removed in Squid version 6.0.1

 If you are using a prepackaged version of Squid then please refer
 to the package vendor for availability information on updated
 packages.

__________________________________________________________________

Determining if your version is vulnerable:

 All Squid-2.x up to and including 2.7.STABLE9 are vulnerable.

 All Squid-3.x up to and including 3.5.28 are vulnerable.

 All Squid-4.x up to and including 4.14 are vulnerable.

 All Squid-5.x up to and including 5.6 are vulnerable.

__________________________________________________________________

Workaround:

 * Reject all gopher URL requests

  acl gopher proto gopher
  http_access deny gopher

 Note: removing the gopher port 70 from the Safe_ports ACL
       is not sufficient to avoid this vulnerability.
__________________________________________________________________

Contact details for the Squid project:

 For installation / upgrade support on binary packaged versions
 of Squid: Your first point of contact should be your binary
 package vendor.

 If you install and build Squid from the original Squid sources
 then the <squid-us...@lists.squid-cache.org> mailing list is your
 primary support point. For subscription details see
 <http://www.squid-cache.org/Support/mailing-lists.html>.

 For reporting of non-security bugs in the latest STABLE release
 the squid bugzilla database should be used
 <https://bugs.squid-cache.org/>.

 For reporting of security sensitive bugs send an email to the
 <squid-b...@lists.squid-cache.org> mailing list. It's a closed
 list (though anyone can post) and security related bug reports
 are treated in confidence until the impact has been established.

__________________________________________________________________

Credits:

 This vulnerability was discovered by Marco Grassi.

__________________________________________________________________

Revision history:

 2019-06-15 13:32:50 UTC Initial Report
__________________________________________________________________
END
_______________________________________________
squid-announce mailing list
squid-announce@lists.squid-cache.org
https://lists.squid-cache.org/listinfo/squid-announce

Reply via email to