An Improper Check for Unusual or Exceptional Conditions vulnerability in Juniper DHCP Daemon (jdhcpd) of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause the jdhcpd to consume all the CPU cycles resulting in a Denial of Service (DoS).
On Junos OS devices with forward-snooped-client configured, if an attacker sends a specific DHCP packet to a non-configured interface, this will cause an infinite loop. The DHCP process will have to be restarted to recover the service.
This issue affects:
Juniper Networks Junos OS
All versions earlier than 20.4R3-S9;
21.2 versions earlier than 21.2R3-S7;
21.3 versions earlier than 21.3R3-S5;
21.4 versions earlier than 21.4R3-S5;
22.1 versions earlier than 22.1R3-S4;
22.2 versions earlier than 22.2R3-S3;
22.3 versions earlier than 22.3R3-S2;
22.4 versions earlier than 22.4R2-S2, 22.4R3;
23.2 versions earlier than 23.2R2.
To be affected a device must be configured with:
[ forwarding-options dhcp-relay group <group-name> interface ... ]
or
[ system services dhcp-local-server group <group-name> interface ... ]
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
This issue was seen during production usage.
This issue has been assigned CVE-2023-36842.
The following software releases have been updated to resolve this specific issue: 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S2, 22.4R2-S2, 22.4R3, 23.2R1-S2, 23.2R2, 23.4R1, and all subsequent releases.
This issue is being tracked as PR 1706709 which is visible on the Customer Support website.
Note: Juniper SIRT's policy [juniper.net] is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).
There are no known workarounds for this issue.
2024-01-10: Initial Publication