CVE-2023-41045

Description

### 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 (CLIENT_QUERY) are depicted in purple, while the queries sent from the recursive DNS server to the authoritatives (RESOLVER_QUERY) 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.  ### 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)

How to fix CVE-2023-41045

To remediate CVE-2023-41045, upgrade the affected package to a fixed version below.

• —upgrade to 5.1.3 or later

Is CVE-2023-41045 being exploited?

Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.

Affected packages (1)