2018-10 Security Bulletin: Junos OS: authd allows assignment of IP address requested by DHCP subscriber logging in with Option 50 (Requested IP Address) (CVE-2018-0057)

Product Affected:

This issue affects Junos OS 15.1, 16.1, 16.2, 17.1, 17.2, 17.3, 17.4, 18.1.

Problem:

On MX Series and M120/M320 platforms configured in a Broadband Edge (BBE) environment, subscribers logging in with DHCP Option 50 to request a specific IP address will be assigned the requested IP address, even if there is a static MAC to IP address binding in the access profile. In the problem scenario, with a hardware-address and IP address configured under address-assignment pool, if a subscriber logging in with DHCP Option 50, the subscriber will not be assigned an available address from the matched pool, but will still get the requested IP address.

A malicious DHCP subscriber may be able to utilize this vulnerability to create duplicate IP address assignments, leading to a denial of service for valid subscribers or unauthorized information disclosure via IP address assignment spoofing.

Affected releases are Juniper Networks Junos OS:

15.1 versions prior to 15.1R7-S2, 15.1R8;
16.1 versions prior to 16.1R4-S12, 16.1R7-S2, 16.1R8;
16.2 versions prior to 16.2R2-S7, 16.2R3;
17.1 versions prior to 17.1R2-S9, 17.1R3;
17.2 versions prior to 17.2R1-S7, 17.2R2-S6, 17.2R3;
17.3 versions prior to 17.3R2-S4, 17.3R3;
17.4 versions prior to 17.4R2;
18.1 versions prior to 18.1R2-S3, 18.1R3.

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-2018-0057.

Solution:

The following software releases have been updated to resolve this specific issue: 15.1R7-S2, 15.1R8, 16.1R4-S12, 16.1R7-S2, 16.1R8, 16.2R2-S7, 16.2R3, 17.1R2-S9, 17.1R3, 17.2R1-S7, 17.2R2-S6, 17.2R3, 17.3R2-S4, 17.3R3, 17.4R2, 18.1R2-S3, 18.1R3, 18.2R1, 18.3R1, and all subsequent releases.

This issue is being tracked as PR 1351334 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).

Workaround:

There are no viable workarounds for this issue.

Implementation:

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

Modification History:

2018-10-10: Initial publication

CVSS Score:

6.1 (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:L)

Severity Level:

Medium

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