[squid-announce] [ADVISORY] SQUID-2021:3 Denial of Service issue in Cache Manager

[squid3 at treenet.co.nz]

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Squid Proxy Cache Security Update Advisory SQUID-2021:3
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Advisory ID:       | SQUID-2021:3
Date:              | May 10, 2021
Summary:           | Denial of Service issue in Cache Manager
Affected versions: | Squid 1.x -> 3.5.28
                    | Squid 4.x -> 4.14
                    | Squid 5.x -> 5.0.4
Fixed in version:  | Squid 4.15 and 5.0.5
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   <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-28652>
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Problem Description:

  Due to an incorrect parser validation bug Squid is vulnerable to
  a Denial of Service attack against the Cache Manager API.

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Severity:

  This problem allows a trusted client to trigger memory leaks
  which over time lead to a Denial of Service against Squid and
  the machine it is operating on.

  This attack is limited to clients with Cache Manager API access
  privilege.

CVSS Score of 7.8
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H/E:F/RL:O/RC:C/CR:X/IR:X/AR:H/MAV:N/MAC:H/MPR:H/MUI:N/MS:C/MC:X/MI:X/MA:H&version=3.1

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Updated Packages:

This bug is fixed by Squid versions 4.15 and 5.0.6.

  In addition, patches 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-4-0003e3518dc95e4b5ab46b5140af79b22253048e.patch>

Squid 5:
  
<http://www.squid-cache.org/Versions/v5/changesets/squid-5-2db70e04723cedd19a90dba8b863ccbc2e708f8e.patch>

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

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Determining if your version is vulnerable:

  Squid older than 3.5.28 have not been tested and should be
  assumed to be vulnerable.

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

  All Squid-5.x up to and including 5.0.4 are vulnerable.

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Workaround:

Either,

  Disable Cache Manager access entirely if not needed.

  Place the following line in squid.conf before lines containing
  "allow" :

    http_access deny manager

Or,

  Harden Cache Manager access privileges.

  For example; require authentication or other access controls in
  http_access beyond the default IP address restriction.

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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-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.

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Credits:

  This vulnerability was discovered by Joshua Rogers of Opera
  Software.

  Fixed by Amos Jeffries of Treehouse Networks Ltd.

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Revision history:

  2021-03-03 17:02:25 UTC Initial Report
  2021-03-16 01:59:45 UTC Patch Released
  2021-03-17 06:19:09 UTC CVE Assignment
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