Amos Jeffries
2018-10-28 16:09:05 UTC
__________________________________________________________________
Squid Proxy Cache Security Update Advisory SQUID-2018:5
__________________________________________________________________
Advisory ID: SQUID-2018:5
Date: October 28, 2018
Summary: Denial of Service issue
in SNMP processing.
Affected versions: Squid 3.2.0.10 -> 3.5.28
Squid 4.x -> 4.3
Fixed in version: Squid 4.4
__________________________________________________________________
http://www.squid-cache.org/Advisories/SQUID-2018_5.txt
__________________________________________________________________
Problem Description:
Due to a memory leak in SNMP query rejection code, Squid is
vulnerable to a denial of service attack.
__________________________________________________________________
Severity:
This problem allows a remote attacker to consume all memory
available to the Squid process, causing it to crash.
In environments where per-process memory restrictions are not
enforced strictly, or configured to large values this may also
affect other processes operating on the same machine. Leading to
a much worse denial of service situation.
This problem is limited to Squid built with SNMP support and
receiving SNMP traffic.
__________________________________________________________________
Updated Packages:
This bug is fixed by Squid version 4.4.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 3.5:
http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-bc9786119f058a76ddf0625424bc33d36460b9a2.patch
Squid 4:
http://www.squid-cache.org/Versions/v4/changesets/squid-4-983c5c36e5f109512ed1af38a329d0b5d0967498.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 built with --disable-snmp are not vulnerable.
All Squid-2.x and older versions are not vulnerable.
All Squid-3.x up to and including 3.2.0.9 are not vulnerable.
All Squid-3.x up to and including 3.5.28 configured with
"snmp_port 0" are not vulnerable.
All Squid-3.x up to and including 3.5.28 without snmp_port
configured are not vulnerable.
All Squid-3.2.0.10 and later 3.2.x versions with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.3 versions up to and including 3.3.14 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.4 versions up to and including 3.4.14 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.5 versions up to and including 3.5.28 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-4.x versions up to and including 4.3 with snmp_port
configured to a non-0 value are vulnerable.
To determine the version of your Squid and its build options use
the command:
squid -v
To determine whether snmp_port is configured use the command:
squid -k parse | grep snmp_port
__________________________________________________________________
Workarounds:
Either;
Enable firewall inspection of SNMP packets to enforce blocking
of any non-permitted packets prior to their arriving at Squid.
This restriction of packet sources reduces the risk, but does not
completely remove the vulnerability.
Or,
Remove snmp_port and related configuration settings until Squid
can be upgraded to a fixed build.
This completely removes the vulnerability at cost of reduced
management and monitoring capabilities.
__________________________________________________________________
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-***@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-***@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 Florian Kohnhäuser
__________________________________________________________________
Revision history:
2018-10-23 06:15:46 UTC Initial Report
2018-10-23 21:42:58 UTC Patch Released
2018-10-27 21:19:00 UTC Packages Released
__________________________________________________________________
END
Squid Proxy Cache Security Update Advisory SQUID-2018:5
__________________________________________________________________
Advisory ID: SQUID-2018:5
Date: October 28, 2018
Summary: Denial of Service issue
in SNMP processing.
Affected versions: Squid 3.2.0.10 -> 3.5.28
Squid 4.x -> 4.3
Fixed in version: Squid 4.4
__________________________________________________________________
http://www.squid-cache.org/Advisories/SQUID-2018_5.txt
__________________________________________________________________
Problem Description:
Due to a memory leak in SNMP query rejection code, Squid is
vulnerable to a denial of service attack.
__________________________________________________________________
Severity:
This problem allows a remote attacker to consume all memory
available to the Squid process, causing it to crash.
In environments where per-process memory restrictions are not
enforced strictly, or configured to large values this may also
affect other processes operating on the same machine. Leading to
a much worse denial of service situation.
This problem is limited to Squid built with SNMP support and
receiving SNMP traffic.
__________________________________________________________________
Updated Packages:
This bug is fixed by Squid version 4.4.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 3.5:
http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-bc9786119f058a76ddf0625424bc33d36460b9a2.patch
Squid 4:
http://www.squid-cache.org/Versions/v4/changesets/squid-4-983c5c36e5f109512ed1af38a329d0b5d0967498.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 built with --disable-snmp are not vulnerable.
All Squid-2.x and older versions are not vulnerable.
All Squid-3.x up to and including 3.2.0.9 are not vulnerable.
All Squid-3.x up to and including 3.5.28 configured with
"snmp_port 0" are not vulnerable.
All Squid-3.x up to and including 3.5.28 without snmp_port
configured are not vulnerable.
All Squid-3.2.0.10 and later 3.2.x versions with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.3 versions up to and including 3.3.14 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.4 versions up to and including 3.4.14 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-3.5 versions up to and including 3.5.28 with snmp_port
configured to a non-0 value are vulnerable.
All Squid-4.x versions up to and including 4.3 with snmp_port
configured to a non-0 value are vulnerable.
To determine the version of your Squid and its build options use
the command:
squid -v
To determine whether snmp_port is configured use the command:
squid -k parse | grep snmp_port
__________________________________________________________________
Workarounds:
Either;
Enable firewall inspection of SNMP packets to enforce blocking
of any non-permitted packets prior to their arriving at Squid.
This restriction of packet sources reduces the risk, but does not
completely remove the vulnerability.
Or,
Remove snmp_port and related configuration settings until Squid
can be upgraded to a fixed build.
This completely removes the vulnerability at cost of reduced
management and monitoring capabilities.
__________________________________________________________________
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-***@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-***@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 Florian Kohnhäuser
__________________________________________________________________
Revision history:
2018-10-23 06:15:46 UTC Initial Report
2018-10-23 21:42:58 UTC Patch Released
2018-10-27 21:19:00 UTC Packages Released
__________________________________________________________________
END