A Use After Free vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
When web filtering for TCP traffic is configured, a high volume of DNS requests increases the likelihood of a flowd crash and restart, which leads to a complete service outage until the service has automatically recovered. This is a race condition outside the attackers direct control.
This issue affects Junos OS on SRX Series:
- All versions before 23.2R2-S5;
- from 23.4 before 23.4R2-S6;
- from 24.2 before 24.2R2-S3;
- from 24.4 before 24.4R2-S1;
- from 25.2 before 25.2R1-S1, 25.2R2.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.