[squid-announce] [ADVISORY] SQUID-2019:11 Information Disclosure issue in HTTP Digest Authentication

[Amos Jeffries]

__________________________________________________________________

    Squid Proxy Cache Security Update Advisory SQUID-2019:11
__________________________________________________________________

Advisory ID:        SQUID-2019:11
Date:               November 05, 2019
Summary:            Information Disclosure issue
                    in HTTP Digest Authentication.
Affected versions:  Squid 2.x -> 2.7.STABLE9
                    Squid 3.x -> 3.5.28
                    Squid 4.x -> 4.8
Fixed in version:   Squid 4.9
__________________________________________________________________

    http://www.squid-cache.org/Advisories/SQUID-2019_11.txt
    http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-18679
__________________________________________________________________

Problem Description:

 Due to incorrect data management Squid is vulnerable to a
 information disclosure when processing HTTP Digest
 Authentication.

__________________________________________________________________

Severity:

 Nonce tokens contain the raw byte value of a pointer which sits
 within heap memory allocation. This information reduces ASLR
 protections and may aid attackers isolating memory areas to
 target for remote code execution attacks.

__________________________________________________________________

Updated Packages:

 This bug is fixed by Squid version 4.9.

 In addition, a patch addressing this problem for the stable
 releases can be found in our patch archives:

Squid 4:
 <http://www.squid-cache.org/Versions/v4/changesets/squid-4-671ba97abe929156dc4c717ee52ad22fba0f7443.patch>

 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 4.8 are vulnerable.

__________________________________________________________________

Workarounds:

Either;

 Remove 'auth_param digest ...' configuration settings from
 squid.conf.

Or,

 Build Squid with --disable-auth-digest

__________________________________________________________________

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 your install and build Squid from the original Squid sources
 then the squid-users at 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
 <http://bugs.squid-cache.org/>.

 For reporting of security sensitive bugs send an email to the
 squid-bugs at 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 and fixed by David Fifield.

__________________________________________________________________

Revision history:

 2019-08-05 06:15:36 UTC Initial Report
 2019-10-20 18:59:08 UTC Patches Released
 2019-11-04 13:43:22 UTC CVE Assignment
__________________________________________________________________
END