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Squid Proxy Cache Security Update Advisory SQUID-2020:6
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Advisory ID: | SQUID-2020:6
Date: | June 19, 2020
Summary: | Denial of Service issue in TLS Handshake
Affected versions: | Squid 3.1 -> 3.5.28
| Squid 4.x -> 4.11
| Squid 5.x -> 5.0.2
Fixed in version: | Squid 4.12 and 5.0.3
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<http://www.squid-cache.org/Advisories/SQUID-2020_6.txt>
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14058>
<https://github.com/squid-cache/squid/security/advisories/GHSA-qvf6-485q-vm57>
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Problem Description:
Due to use of a potentially dangerous function Squid and the
default certificate validation helper are vulnerable to a Denial
of Service attack when processing TLS certificates.
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Severity:
This problem allows a trusted client to perform Denial of Service
when opening TLS connections with a server for HTTPS.
This problem allows a trusted client to perform Denial of Service
when opening TLS connections to a server for SSL-Bump intercepted
transactions.
This attack is limited to Squid built with OpenSSL features and
opening peer or server connections for HTTPS traffic and SSL-Bump
server handshakes.
CVSS Score of 8.3
<https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/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:N/MUI:X/MS:C/MC:N/MI:N/MA:H&version=3.1>
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Updated Packages:
This bug is fixed by Squid versions 4.12 and 5.0.3.
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-4-93f5fda134a2a010b84ffedbe833d670e63ba4be.patch>
Squid 5:
<http://www.squid-cache.org/Versions/v5/changesets/squid-5-c6d1a4f6a2cbebceebc8a3fcd8f539ceb7b7f723.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:
All Squid-2.x up to and including 2.7.STABLE9 are not vulnerable.
All Squid-3.x up to and including 3.4.14 built without
--enable-openssl are not vulnerable.
All Squid-3.x up to and including 3.4.14 built with
--disable-openssl are not vulnerable.
All Squid-3.x up to and including 3.4.14 built with
--enable-openssl are vulnerable.
All Squid-3.5 up to and including 3.5.28 built without
--with-openssl are not vulnerable.
All Squid-3.5 up to and including 3.5.28 built with
--without-openssl are not vulnerable.
All Squid-3.5 up to and including 3.5.28 built with
--with-openssl are vulnerable.
All Squid-4.x up to and including 4.11 built without
--with-openssl are not vulnerable.
All Squid-4.x up to and including 4.11 built with
--without-openssl are not vulnerable.
All Squid-4.x up to and including 4.11 built with --with-openssl
are vulnerable.
Squid-5.0.1 and 5.0.2 built without --with-openssl are not
vulnerable.
Squid-5.0.1 and 5.0.2 built with --without-openssl are not
vulnerable.
Squid-5.0.1 and 5.0.2 built with --with-openssl are vulnerable.
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Workaround:
* For interception proxies using SSL-Bump functionality there is
no workaround.
* For reverse-proxy the GnuTLS support available in Squid-4 may
provide sufficient functionality. The vulnerable certificate
validator helper feature is not supported yet by GnuTLS builds.
* Other installations just needing to relay HTTPS do not need
OpenSSL support and should be able to run a build that does not
have --with-openssl.
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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@xxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxx> 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 Dimitra Azariadi and Mario
Galli of Open Systems AG.
Fixed by Christos Tsantilas of The Measurement Factory.
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Revision history:
2020-03-04 09:31:23 UTC Initial Report
2020-05-15 04:54:54 UTC Patches Released
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END
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