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Squid Proxy Cache Security Update Advisory SQUID-2020:5
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Advisory ID: | SQUID-2020:5
Date: | June 19, 2020
Summary: | Denial of Service when using SMP cache
Affected versions: | 5.0.1 -> 5.0.2
Fixed in version: | 5.0.3
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<http://www.squid-cache.org/Advisories/SQUID-2020_5.txt>
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14059>
<https://github.com/squid-cache/squid/security/advisories/GHSA-w7pw-2m4p-58hr>
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Problem Description:
Due to an Incorrect Synchronization, Squid is vulnerable to a
Denial of Service attack when processing objects in an SMP cache.
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Severity:
This problem may allow a remote client to trigger a Squid worker
assertion.
This attack is limited to SMP Squids using shared memory cache
and/or an SMP rock disk cache.
CVSS Score of 7.3
<https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C/CR:X/IR:X/AR:H/MAV:N/MAC:H/MPR:L/MUI:N/MS:C/MC:N/MI:X/MA:H&version=3.1>
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Updated Packages:
This bug is fixed in Squid version 5.0.3.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 5:
<http://www.squid-cache.org/Versions/v5/changesets/squid-5-7a5af8db8e0377c06ed9ffbdcb1334389c7cd8ab.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-3.x up to and including 3.5.28 are not vulnerable.
All Squid-4.x up to and including 4.12 are not vulnerable.
Squid-5.0.1 and 5.0.2 not using SMP caching are not vulnerable.
Squid-5.0.1 and 5.0.2 using SMP caching are vulnerable.
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Workarounds:
Disable all SMP caching. For example:
* If using multiple Squid workers, set 'cache_mem' to '0' and
remove all `cache_dir` directives from squid.conf.
* If using a single Squid worker, remove all 'cache_dir rock'
directives from squid.conf.
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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 your 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 Jack Zar of Bloomberg.
Fixed by Alex Rousskov of The Measurement Factory.
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Revision history:
2020-03-02 16:45:44 UTC Initial Report
2020-05-13 06:37:31 UTC Patch Released
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END
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