2020-10 Security Bulletin: Junos OS: jdhcpd process crash when processing a specific DHCPDv6 packet in DHCPv6 relay configuration. (CVE-2020-1672)

Product Affected:

This issue affects Junos OS 17.3, 17.4, 18.1, 18.2, 18.2X75, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1.

Problem:

On Juniper Networks Junos OS devices configured with DHCPv6 relay enabled, receipt of a specific DHCPv6 packet might crash the jdhcpd daemon.

The jdhcpd daemon automatically restarts without intervention, but continuous receipt of specific crafted DHCP messages will repeatedly crash jdhcpd, leading to an extended Denial of Service (DoS) condition.

Only DHCPv6 packet can trigger this issue. DHCPv4 packet cannot trigger this issue.

This issue affects Juniper Networks Junos OS:

17.3 versions prior to 17.3R3-S9;
17.4 versions prior to 17.4R2-S11, 17.4R3-S2, 17.4R3-S3;
18.1 versions prior to 18.1R3-S11;
18.2 versions prior to 18.2R3-S5;
18.3 versions prior to 18.3R2-S4, 18.3R3-S3;
18.4 versions prior to 18.4R2-S5, 18.4R3-S4;
19.1 versions prior to 19.1R2-S2, 19.1R3-S2;
19.2 versions prior to 19.2R1-S5, 19.2R2-S1, 19.2R3;
19.3 versions prior to 19.3R2-S4, 19.3R2-S4, 19.3R3;
19.4 versions prior to 19.4R1-S3, 19.4R2-S1, 19.4R3;
20.1 versions prior to 20.1R1-S3, 20.1R2.

The example of the config stanza affected by this issue:

[forwarding-options dhcp-relay dhcpv6]

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-2020-1672.

Solution:

The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 17.4R3-S3, 18.1R3-S11, 18.2R3-S5, 18.2X75-D34, 18.2X75-D65, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3-S2, 19.2R1-S5, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S1, 19.4R3, 20.1R1-S3, 20.1R2, 20.2R1, 20.3X75-D10, and all subsequent releases.

This issue is being tracked as 1512765.

Workaround:

There are no viable workarounds for this issue.

Implementation:

Software releases or updates are available for download at https://www.juniper.net/support/downloads/.

Modification History:

2020-10-14: Initial Publication.

CVSS Score:

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

Severity Level:

High

Severity Assessment:

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

Knowledge Base