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AUSCERT External Security Bulletin Redistribution
ESB-2024.0084
K83120834 : Diffie-Hellman key agreement protocol weaknesses
CVE-2002-20001 & CVE-2022-40735
3 January 2024
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: BIG-IP (APM)
BIG-IP (all modules)
BIG-IP SPK
BIG-IQ Centralized Management
F5OS-A
F5OS-C
Traffix SDC
Publisher: F5 Networks
Operating System: Network Appliance
Resolution: Mitigation
CVE Names: CVE-2022-40735 CVE-2002-20001
Original Bulletin:
https://my.f5.com/manage/s/article/K83120834
Comment: CVSS (Max): 7.5 CVE-2022-40735 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS Source: F5 Networks
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- --------------------------BEGIN INCLUDED TEXT--------------------
K83120834: Diffie-Hellman key agreement protocol weaknesses CVE-2002-20001 &
CVE-2022-40735
Published Date: May 19, 2022
Updated Date: Jan 2, 2024
Security Advisory Description
o The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the
client side) to send arbitrary numbers that are actually not public keys,
and trigger expensive server-side DHE modular-exponentiation calculations,
aka a D(HE)ater attack. The client needs very little CPU resources and
network bandwidth. The attack may be more disruptive in cases where a
client can require a server to select its largest supported key size. The
basic attack scenario is that the client must claim that it can only
communicate with DHE, and the server must be configured to allow DHE. (
CVE-2002-20001)
o The Diffie-Hellman Key Agreement Protocol allows use of long exponents that
arguably make certain calculations unnecessarily expensive, because the
1996 van Oorschot and Wiener paper found that "(appropriately) short
exponents" can be used when there are adequate subgroup constraints, and
these short exponents can lead to less expensive calculations than for long
exponents. This issue is different from CVE-2002-20001 because it is based
on an observation about exponent size, rather than an observation about
numbers that are not public keys. The specific situations in which
calculation expense would constitute a server-side vulnerability depend on
the protocol (e.g., TLS, SSH, or IKE) and the DHE implementation details.
In general, there might be an availability concern because of server-side
resource consumption from DHE modular-exponentiation calculations. Finally,
it is possible for an attacker to exploit this vulnerability and
CVE-2002-20001 together. (CVE-2022-40735)
Impact
This vulnerability allows remote attackers (from the client side) to send
arbitrary numbers that are actually not public keys, and trigger expensive
server-side DHE modular-exponentiation calculations, also known as a D(HE)ater
attack.
There could be an increase in CPU usage in the affected component. For OpenSSH,
users may observe issues such as a slowdown in SSH connections.
Security Advisory Status
F5 Product Development has assigned IDs 1083281, 1083937, 1093813 (BIG-IP),
1083281-6, 1083937-1 (BIG-IQ), 1086037 (F5OS-A), 1086001 (F5OS-C) and SDC-1752,
SDC-1753 (Traffix SDC) to this vulnerability.
To determine if your product and version have been evaluated for this
vulnerability, refer to the Evaluated products box. To determine if your
release is known to be vulnerable, the components or features that are affected
by the vulnerability, and for information about releases, point releases, or
hotfixes that address the vulnerability, refer to the following tables. You can
also use iHealth to diagnose a vulnerability for BIG-IP and BIG-IQ systems. For
more information about using iHealth, refer to K27404821: Using F5 iHealth to
diagnose vulnerabilities. For more information about security advisory
versioning, refer to K51812227: Understanding security advisory versioning.
In this section
o BIG-IP and BIG-IQ
o F5OS
o NGINX
o Other products
BIG-IP and BIG-IQ
Note: After a fix is introduced for a given minor branch, that fix applies to
all subsequent maintenance and point releases for that branch, and no
additional fixes for that branch will be listed in the table. For example, when
a fix is introduced in 14.1.2.3, the fix also applies to 14.1.2.4, and all
later 14.1.x releases (14.1.3.x., 14.1.4.x). For more information, refer to
K51812227: Understanding security advisory versioning.
+-----------+------+-----------+----------+--------+------+-------------------+
| | |Versions |Fixes | |CVSSv3|Vulnerable |
|Product |Branch|known to be|introduced|Severity|score^|component or |
| | |vulnerable^|in | |2 |feature |
| | |1 | | | | |
+-----------+------+-----------+----------+--------+------+-------------------+
| |17.x |17.0.0 |17.1.0 | | |APM server |
| | | | | | |components |
| +------+-----------+----------+ | |including, but not |
| | |16.1.0 - | | | |limited to: |
| |16.x |16.1.3 |16.1.4 | | | |
| | | | | | | o Access Policy |
| +------+-----------+----------+ | | Evaluation |
| | |15.1.0 - | | | | o OAuth |
|BIG-IP |15.x |15.1.9 |None |High |7.5 | Authorization |
|(APM) | | | | | | Server |
| +------+-----------+----------+ | | o SAML IdP |
| | |14.1.0 - |Will not | | | o Privileged User|
| |14.x |14.1.5 |fix | | | Access (WebSSH |
| | | | | | | resource SSH |
| +------+-----------+----------+ | | configuration, |
| | |13.1.0 - |Will not | | | LDAPS Proxy, |
| |13.x |13.1.5 |fix | | | and Radius |
| | | | | | | Proxy) |
+-----------+------+-----------+----------+--------+------+-------------------+
| |17.x |17.0.0 - |Will not | | | |
| | |17.1.0 |fix | | | |
| +------+-----------+----------+ | | |
| |16.x |16.1.0 - |Will not | | |Control plane: |
| | |16.1.4 |fix | | |httpd |
| +------+-----------+----------+ | | |
|BIG-IP (all|15.x |15.1.0 - |Will not |High |7.5 |Data plane: |
|modules) | |15.1.9 |fix | | |TMM (Client SSL and|
| +------+-----------+----------+ | |Server SSL profiles|
| |14.x |14.1.0 - |Will not | | |with DHE ciphers) |
| | |14.1.5 |fix | | | |
| +------+-----------+----------+ | | |
| |13.x |13.1.0 - |Will not | | | |
| | |13.1.5 |fix | | | |
+-----------+------+-----------+----------+--------+------+-------------------+
| |17.x |17.0.0 - |Will not | | | |
| | |17.1.0 |fix | | | |
| +------+-----------+----------+ | | |
| |16.x |16.1.0 - |Will not | | | |
| | |16.1.4 |fix | | | |
| +------+-----------+----------+ | | |
|BIG-IP (all|15.x |15.1.0 - |Will not |Medium |6.2 |OpenSSH |
|modules) | |15.1.9 |fix | | | |
| +------+-----------+----------+ | | |
| |14.x |14.1.0 - |Will not | | | |
| | |14.1.5 |fix | | | |
| +------+-----------+----------+ | | |
| |13.x |13.1.0 - |Will not | | | |
| | |13.1.5 |fix | | | |
+-----------+------+-----------+----------+--------+------+-------------------+
|BIG-IP SPK |1.x |1.6.0 |None |High |7.5 |TMM |
+-----------+------+-----------+----------+--------+------+-------------------+
| |8.x |8.0.0 - |None | | | |
|BIG-IQ | |8.3.0 | | | | |
|Centralized+------+-----------+----------+High |7.5 |httpd |
|Management |7.x |7.1.0 |Will not | | | |
| | | |fix | | | |
+-----------+------+-----------+----------+--------+------+-------------------+
| |8.x |8.0.0 - |None | | | |
|BIG-IQ | |8.3.0 | | | | |
|Centralized+------+-----------+----------+Medium |6.2 |OpenSSH |
|Management |7.x |7.1.0 |Will not | | | |
| | | |fix | | | |
+-----------+------+-----------+----------+--------+------+-------------------+
^1F5 evaluates only software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle. For more information, refer
to the Security hotfixes section of K4602: Overview of the F5 security
vulnerability response policy.
^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.
F5OS
+-------+------+-----------------+----------+--------+-------+----------------+
| | |Versions known to|Fixes | |CVSSv3 |Vulnerable |
|Product|Branch|be vulnerable^1 |introduced|Severity|score^2|component or |
| | | |in | | |feature |
+-------+------+-----------------+----------+--------+-------+----------------+
|F5OS-A |1.x |1.3.0 - 1.3.1 |None |Medium |6.2 |OpenSSH |
+-------+------+-----------------+----------+--------+-------+----------------+
|F5OS-C |1.x |1.5.0 - 1.5.1 |None |Medium |6.2 |OpenSSH |
| | |1.3.0 - 1.3.2 | | | | |
+-------+------+-----------------+----------+--------+-------+----------------+
^1F5 evaluates only software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle. For more information, refer
to the Security hotfixes section of K4602: Overview of the F5 security
vulnerability response policy.
^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.
NGINX
+----------+------+---------------+----------+----------+------+--------------+
| | |Versions known |Fixes | |CVSSv3|Vulnerable |
|Product |Branch|to be |introduced|Severity |score^|component or |
| | |vulnerable^1 |in | |2 |feature |
+----------+------+---------------+----------+----------+------+--------------+
|NGINX (all|All |None |Not |Not |None |None |
|products )| | |applicable|vulnerable| | |
+----------+------+---------------+----------+----------+------+--------------+
^1F5 evaluates only software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle. For more information, refer
to the Security hotfixes section of K4602: Overview of the F5 security
vulnerability response policy.
^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.
Other products
+-------+------+-----------------+----------+--------+-------+----------------+
| | |Versions known to|Fixes | |CVSSv3 |Vulnerable |
|Product|Branch|be vulnerable^1 |introduced|Severity|score^2|component or |
| | | |in | | |feature |
+-------+------+-----------------+----------+--------+-------+----------------+
|Traffix|5.x |5.2.0 |SDC 5.2 |High |7.5 |WebUI, Tomcat |
|SDC | |5.1.0 |CF-4 | | |server |
+-------+------+-----------------+----------+--------+-------+----------------+
^1F5 evaluates only software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle. For more information, refer
to the Security hotfixes section of K4602: Overview of the F5 security
vulnerability response policy.
^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.
Security Advisory Recommended Actions
If you are running a version listed in the Versions known to be vulnerable
column, you can eliminate this vulnerability by installing a version listed in
the Fixes introduced in column. If the Fixes introduced in column does not list
a version for your branch, then no update candidate currently exists for that
branch and F5 recommends that you upgrade to a version with the fix (refer to
the tables).
If the Fixes introduced in column lists a version prior to the one you are
running, in the same branch, then your version should have the fix.
Mitigation
The following mitigations are currently available. Additional mitigations may
become available in the future as this security advisory is investigated
further.
o BIG-IP (control plane)
? httpd
? OpenSSH
o BIG-IP (data plane)
o BIG-IQ
? httpd
? OpenSSH
o Traffix SDC
? WebUI, Tomcat server
BIG-IP (control plane)
httpd
Do not use DHE ciphers in the httpd service. For more information, refer to
K02321234: Managing the SSL protocols and ciphers allowed by Configuration
utility.
Note: The httpd service's default cipher-string in the BIG-IP system uses only
ECDHE and RSA for key exchange and is, therefore, not vulnerable by default.
OpenSSH
Two possible mitigations are available:
o Beginning in BIG-IP 15.1.x, you can enable Common Criteria mode by enabling
the security.commoncriteria DB variable. To do so, enter the following
command on the bash shell:
tmsh modify sys db security.commoncriteria value true
Note: This command requires that the BIG-IP system is restarted before the
new mode takes effect. The BIG-IP system continues to operate until this is
complete.
o Do not use DHE ciphers in the OpenSSH service. For more information about
removing DHE ciphers, refer to K80425458: Modifying the list of ciphers and
MAC and key exchange algorithms used by the SSH service on the BIG-IP or
BIG-IQ systems.
BIG-IP (data plane)
Configure Client SSL and Server SSL profiles to not use DHE ciphers. Use a
cipher group/suite that does not use DHE ciphers. To do so, refer to the
following articles:
o K01770517: Configuring the cipher strength for SSL profiles (14.x - 17.x)
o K10866411: Creating a custom cipher group using the Configuration utility.
Note: The default Client SSL and Server SSL profiles use DHE ciphers.
BIG-IQ
httpd
Do not use DHE ciphers in the httpd service.
Note: The httpd service's default cipher-string in the BIG-IQ system uses only
ECDHE and RSA for key exchange and is, therefore, not vulnerable by default.
OpenSSH
Two possible mitigations are available:
o Beginning in BIG-IQ 8.x, you can enable Common Criteria mode by enabling
the security.commoncriteria DB variable. To do so, enter the following
command on the bash shell:
tmsh modify sys db security.commoncriteria value true
o Do not use DHE ciphers in the OpenSSH service. For more information about
removing DHE ciphers, refer to K80425458: Modifying the list of ciphers and
MAC and key exchange algorithms used by the SSH service on the BIG-IP or
BIG-IQ systems.
Traffix SDC
WebUI, Tomcat server
Configure Tomcat to not use DHE ciphers. To do so, perform the following:
1. Log in by way of SSH to the EMS machine.
2. Edit the file /opt/traffix/apache-tomcat-8.5.75/conf/server.xml.
3. From the two ciphers= parameters, remove the following values:
TLS_DHE_RSA_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_128_SHA,TLS_DHE_DSS_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_256_SHA256,TLS_DHE_DSS_WITH_AES_256_SHA,TLS_DHE_RSA_WITH_AES_256_SHA
4. Restart the Tomcat server.
Related Content
o K41942608: Overview of security advisory articles
o K12201527: Overview of Quarterly Security Notifications
o K51812227: Understanding security advisory versioning
o K4602: Overview of the F5 security vulnerability response policy
o K4918: Overview of the F5 critical issue hotfix policy
o K39757430: F5 product and services lifecycle policy index
o K9502: BIG-IP hotfix and point release matrix
o K13123: Managing BIG-IP product hotfixes (11.x - 17.x)
o K15106: Managing BIG-IQ product hotfixes
o K15113: BIG-IQ hotfix and point release matrix
o K48955220: Installing an OPSWAT Endpoint Security update on BIG-IP APM
systems (11.4.x and later)
o K167: Downloading software and firmware from F5
o K9970: Subscribing to email notifications regarding F5 products
o K9957: RSS feed service interruption
o K44525501: Overview of BIG-IP data plane and control plane
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