2023-07 Security Bulletin: Junos OS Evolved: PTX10001-36MR, and PTX10004, PTX10008, PTX10016 with LC1201/1202: The aftman-bt process will crash in a MoFRR scenario (CVE-2023-36833)

Product Affected

This issue affects Junos OS Evolved 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, 22.4. Affected platforms: PTX10001-36MR, PTX10004, PTX10008, PTX10016 with LC1201/1202.

Severity

Medium

Severity Assessment (CVSS) Score

6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Problem

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:

<date> <hostname> evo-aftmand-bt[<pid>]: [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.

To be exposed to this issue an interfaces need to be configured for multicast-only fast reroute (MoFRR) as follows:

[ routing-options multicast stream-protection ]

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-2023-36833.

Solution

The following software releases have been updated to resolve this specific issue: 21.4R3-S3-EVO, 22.2R3-S2-EVO*, 22.3R3-EVO, 22.4R1-S2-EVO, 22.4R2-EVO, 23.1R1-EVO, and all subsequent releases.

This issue is being tracked as 1671799

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Workaround

There are no known workarounds for this issue.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories.

Modification History