CVE-2023-41045: Insecure source port usage for DNS queries in Graylog
Summary Graylog utilises only one single source port for DNS queries.
Details Graylog seems to bind a single socket for outgoing DNS queries. That socket is bound to a random port number which is not changed again. This goes against recommended practice since 2008, when Dan Kaminsky discovered how easy is to carry out DNS cache poisoning attacks. In order to prevent cache poisoning with spoofed DNS responses, it is necessary to maximise the uncertainty in the choice of a source port for a DNS query.
PoC
The attached figure shows the source ports distribution difference between Graylog configured to use a data adapter based on DNS queries and ISC Bind. The source port distribution of the DNS queries sent from Graylog to a recursive DNS name server running Bind (CLIENTQUERY) are depicted in purple, while the queries sent from the recursive DNS server to the authoritatives (RESOLVERQUERY) are plotted in green color. As it can be observed, in contrast to ISC Bind which presents a heterogeneous usage of source port, Graylog utilises a single source port.
!image
Impact Although unlikely in many setups, an external attacker could inject forged DNS responses into a Graylog's lookup table cache. In order to prevent this, it is at least recommendable to distribute the DNS queries through a pool of distinct sockets, each of them with a random source port and renew them periodically.
(Credit to Iratxe Niño from Fundación Sarenet and Borja Marcos from Sarenet)
Other sources
Graylog is a free and open log management platform. Graylog makes use of only one single source port for DNS queries. Graylog binds a single socket for outgoing DNS queries and while that socket is bound to a random port number it is never changed again. This goes against recommended practice since 2008, when Dan Kaminsky discovered how easy is to carry out DNS cache poisoning attacks. In order to prevent cache poisoning with spoofed DNS responses, it is necessary to maximise the uncertainty in the choice of a source port for a DNS query. Although unlikely in many setups, an external attacker could inject forged DNS responses into a Graylog's lookup table cache. In order to prevent this, it is at least recommendable to distribute the DNS queries through a pool of distinct sockets, each of them with a random source port and renew them periodically. This issue has been addressed in versions 5.0.9 and 5.1.3. Users are advised to upgrade. There are no known workarounds for this issue.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2023-41045?
CVE-2023-41045 is a vulnerability in Graylog, a free and open log management platform, which binds a single socket for outgoing DNS queries and does not change the port number.
What is the severity of CVE-2023-41045?
CVE-2023-41045 has a severity value of 5.3, which is considered medium.
How does CVE-2023-41045 affect Graylog?
CVE-2023-41045 affects Graylog versions up to 5.0.9 and versions from 5.1.0 to 5.1.3.
How can I fix CVE-2023-41045?
To fix CVE-2023-41045, it is recommended to update Graylog to version 5.0.9 or higher, or version 5.1.3 or higher.
Is there any additional information about CVE-2023-41045?
Yes, you can find additional information about CVE-2023-41045 in the references provided: [Reference 1](https://github.com/Graylog2/graylog2-server/commit/466af814523cffae9fbc7e77bab7472988f03c3e), [Reference 2](https://github.com/Graylog2/graylog2-server/commit/a101f4f12180fd3dfa7d3345188a099877a3c327), [Reference 3](https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-g96c-x7rh-99r3).