Summary
CVE-2022-2928 - Results from a failure to re-initialize a field when replying to a DHCPv4 lease query.
CVE-2022-2929 - Failure to free memory allocated when processing DHCPv4 option 81 FQDN values.
Overview
On October 5th, 2022 ISC announced two new vulnerabilities, CVE-2022-2928 and CVE-2022-2929.
- Program Impacted: ISC DHCP
- CVSS Score: 6.5
- CVSS Vector: AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Versions
- NIOS is vulnerable to CVE-2022-2928 and CVE-2022-2929.
- BloxOne and NetMRI are not vulnerable to these issues.
Impact
CVE-2022-2928 - This issue results in a counter overflow that can trigger an unsolicited DHCP service restart.
With a DHCP server configured with "allow leasequery;", a remote machine with access to the server can send lease queries for the same lease multiple times, leading to the "add_option()" function being repeatedly called. This could cause an option's "refcount" field to overflow and the server to abort. Internally, reference counters are integers and thus overflow at 2^31 references; so even at 1000 lease query responses per second, it would take more than three weeks to crash the server.
CVE-2022-2929 - This issue results in a memory leak that can trigger an unsolicited DHCP service restart.
A system with access to a DHCP server, sending DHCP packets crafted to include "fqdn" labels longer than 63 bytes, could eventually cause the server to run out of memory.
