A Use After Free vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS Evolved on PTX10001-36MR, and PTX10004, PTX10008, PTX10016 with LC1201/1202 allows an adjacent, unauthenticated attacker to cause a Denial of Service (DoS).
The process aftman-bt will crash after multiple flaps on a multicast-only fast reroute (MoFRR) enabled interface. This will cause the respective FPC to stop forwarding traffic and it needs to be rebooted to restore the service.
An indication that the system experienced this issue is the following log message:
evo-aftmand-bt[]: [Error] jexpr_fdb: sanity check failed, … , app_name L3 Mcast Routes
This issue affects Juniper Networks Junos OS Evolved on PTX10001-36MR, PTX10004, PTX10008, PTX10016 with LC1201/1202: 21.2 version 21.2R1-EVO and later versions; 21.3 version 21.3R1-EVO and later versions; 21.4 versions prior to 21.4R3-S3-EVO; 22.1 version 22.1R1-EVO and later versions; 22.2 versions prior to 22.2R3-S2-EVO; 22.3 versions prior to 22.3R3-EVO; 22.4 versions prior to 22.4R1-S2-EVO, 22.4R2-EVO.
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Junos_os_evolved | Juniper | 21.2 (including) | 21.2 (including) |
| Junos_os_evolved | Juniper | 21.2-r1 (including) | 21.2-r1 (including) |
| Junos_os_evolved | Juniper | 21.2-r1-s1 (including) | 21.2-r1-s1 (including) |
| Junos_os_evolved | Juniper | 21.2-r1-s2 (including) | 21.2-r1-s2 (including) |
| Junos_os_evolved | Juniper | 21.2-r2 (including) | 21.2-r2 (including) |
| Junos_os_evolved | Juniper | 21.2-r2-s1 (including) | 21.2-r2-s1 (including) |
| Junos_os_evolved | Juniper | 21.2-r2-s2 (including) | 21.2-r2-s2 (including) |
| Junos_os_evolved | Juniper | 21.2-r3 (including) | 21.2-r3 (including) |
| Junos_os_evolved | Juniper | 21.2-r3-s1 (including) | 21.2-r3-s1 (including) |
| Junos_os_evolved | Juniper | 21.2-r3-s2 (including) | 21.2-r3-s2 (including) |
| Junos_os_evolved | Juniper | 21.2-r3-s3 (including) | 21.2-r3-s3 (including) |
| Junos_os_evolved | Juniper | 21.2-r3-s4 (including) | 21.2-r3-s4 (including) |
| Junos_os_evolved | Juniper | 21.2-r3-s5 (including) | 21.2-r3-s5 (including) |
| Junos_os_evolved | Juniper | 21.3 (including) | 21.3 (including) |
| Junos_os_evolved | Juniper | 21.3-r1 (including) | 21.3-r1 (including) |
| Junos_os_evolved | Juniper | 21.3-r1-s1 (including) | 21.3-r1-s1 (including) |
| Junos_os_evolved | Juniper | 21.3-r2 (including) | 21.3-r2 (including) |
| Junos_os_evolved | Juniper | 21.3-r2-s1 (including) | 21.3-r2-s1 (including) |
| Junos_os_evolved | Juniper | 21.3-r2-s2 (including) | 21.3-r2-s2 (including) |
| Junos_os_evolved | Juniper | 21.3-r3 (including) | 21.3-r3 (including) |
| Junos_os_evolved | Juniper | 21.3-r3-s1 (including) | 21.3-r3-s1 (including) |
| Junos_os_evolved | Juniper | 21.3-r3-s2 (including) | 21.3-r3-s2 (including) |
| Junos_os_evolved | Juniper | 21.3-r3-s3 (including) | 21.3-r3-s3 (including) |
| Junos_os_evolved | Juniper | 21.3-r3-s4 (including) | 21.3-r3-s4 (including) |
| Junos_os_evolved | Juniper | 21.4 (including) | 21.4 (including) |
| Junos_os_evolved | Juniper | 21.4-r1 (including) | 21.4-r1 (including) |
| Junos_os_evolved | Juniper | 21.4-r1-s1 (including) | 21.4-r1-s1 (including) |
| Junos_os_evolved | Juniper | 21.4-r1-s2 (including) | 21.4-r1-s2 (including) |
| Junos_os_evolved | Juniper | 21.4-r2 (including) | 21.4-r2 (including) |
| Junos_os_evolved | Juniper | 21.4-r2-s1 (including) | 21.4-r2-s1 (including) |
| Junos_os_evolved | Juniper | 21.4-r2-s2 (including) | 21.4-r2-s2 (including) |
| Junos_os_evolved | Juniper | 21.4-r3 (including) | 21.4-r3 (including) |
| Junos_os_evolved | Juniper | 21.4-r3-s1 (including) | 21.4-r3-s1 (including) |
| Junos_os_evolved | Juniper | 21.4-r3-s2 (including) | 21.4-r3-s2 (including) |
| Junos_os_evolved | Juniper | 22.1-r1 (including) | 22.1-r1 (including) |
| Junos_os_evolved | Juniper | 22.1-r1-s1 (including) | 22.1-r1-s1 (including) |
| Junos_os_evolved | Juniper | 22.1-r1-s2 (including) | 22.1-r1-s2 (including) |
| Junos_os_evolved | Juniper | 22.1-r2 (including) | 22.1-r2 (including) |
| Junos_os_evolved | Juniper | 22.1-r2-s1 (including) | 22.1-r2-s1 (including) |
| Junos_os_evolved | Juniper | 22.1-r3 (including) | 22.1-r3 (including) |
| Junos_os_evolved | Juniper | 22.1-r3-s1 (including) | 22.1-r3-s1 (including) |
| Junos_os_evolved | Juniper | 22.1-r3-s2 (including) | 22.1-r3-s2 (including) |
| Junos_os_evolved | Juniper | 22.1-r3-s3 (including) | 22.1-r3-s3 (including) |
| Junos_os_evolved | Juniper | 22.2-r1 (including) | 22.2-r1 (including) |
| Junos_os_evolved | Juniper | 22.2-r1-s1 (including) | 22.2-r1-s1 (including) |
| Junos_os_evolved | Juniper | 22.2-r2 (including) | 22.2-r2 (including) |
| Junos_os_evolved | Juniper | 22.2-r2-s1 (including) | 22.2-r2-s1 (including) |
| Junos_os_evolved | Juniper | 22.2-r2-s2 (including) | 22.2-r2-s2 (including) |
| Junos_os_evolved | Juniper | 22.2-r3 (including) | 22.2-r3 (including) |
| Junos_os_evolved | Juniper | 22.2-r3-s1 (including) | 22.2-r3-s1 (including) |
| Junos_os_evolved | Juniper | 22.3-r1 (including) | 22.3-r1 (including) |
| Junos_os_evolved | Juniper | 22.3-r1-s1 (including) | 22.3-r1-s1 (including) |
| Junos_os_evolved | Juniper | 22.3-r1-s2 (including) | 22.3-r1-s2 (including) |
| Junos_os_evolved | Juniper | 22.3-r2 (including) | 22.3-r2 (including) |
| Junos_os_evolved | Juniper | 22.3-r2-s1 (including) | 22.3-r2-s1 (including) |
| Junos_os_evolved | Juniper | 22.4-r1 (including) | 22.4-r1 (including) |
| Junos_os_evolved | Juniper | 22.4-r1-s1 (including) | 22.4-r1-s1 (including) |
The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:
In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.