Product Affected

This issue affects Junos OS 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, 20.3, 20.4, 21.1. Affected platforms: vSRX 3.0.
Medium
5.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L)

Problem

An Out-of-bounds Write vulnerability in the FreeBSD dhclient shipped with Juniper Networks Junos OS vSRX 3.0 allows a adjacent unauthenticated attacker requiring user interaction to cause some impact to confidentiality, integrity and availability.
 

dhclient fails to handle certain malformed input related to handling of DHCP option 119 resulting a heap overflow. The heap overflow could in principle be exploited to achieve remote code execution. The affected process runs with reduced privileges in a Capsicum sandbox, limiting the immediate impact of an exploit.
 

This issue affects Juniper Networks Junos OS on vSRX 3.0 model:

  • 18.4 versions prior to 18.4R2-S10, 18.4R3-S10;
  • 19.1 versions prior to 19.1R3-S7;
  • 19.2 versions prior to 19.2R1-S8, 19.2R3-S4;
  • 19.3 versions prior to 19.3R3-S4;
  • 19.4 versions prior to 19.4R2-S6, 19.4R3-S6;
  • 20.1 versions prior to 20.1R3-S3;
  • 20.2 versions prior to 20.2R3-S3;
  • 20.3 versions prior to 20.3R3-S3;
  • 20.4 versions prior to 20.4R3;
  • 21.1 versions prior to 21.1R2.


Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was discovered during external security research.

This issue has been assigned CVE-2020-7461.

Solution

The following software releases have been updated to resolve this specific issue: 18.4R2-S10, 18.4R3-S10, 19.1R3-S7, 19.2R1-S8, 19.2R3-S4, 19.3R3-S4, 19.4R2-S6, 19.4R3-S6, 20.1R3-S3, 20.2R3-S3, 20.3R3-S3, 20.4R3, 21.1R2, 21.2R1, and all subsequent releases.
 

This issue is being tracked as PR 1589509 which is visible on the Customer Support website.
 

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

Implementation:

Software Releases, patches and updates are available at https://support.juniper.net/support/downloads/

Workaround

There are no viable workarounds for this issue.

To reduce the risk of exploitation of this issue, limit access to the shell to only highly trusted administrators.

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

2022-04-13: Initial Publication.

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