2018-01 Security Bulletin: Junos: bbe-smgd process denial of service while processing VLAN authentication requests/rejects (CVE-2018-0006)

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Product Affected:
This issue affects Junos OS 15.1, 16.1, 16.2, 17.1, 17.2.
Problem:
A high rate of VLAN authentication attempts sent from an adjacent host on the local broadcast domain can trigger high memory utilization by the BBE subscriber management daemon (bbe-smgd), and lead to a denial of service condition. The issue was caused by attempting to process an unbounded number of pending VLAN authentication requests, leading to excessive memory allocation.

This issue only affects devices configured for DHCPv4/v6 over AE auto-sensed VLANs, utilized in Broadband Edge (BBE) deployments. Other configurations are unaffected by this issue.

Affected releases are Juniper Networks Junos OS:
  • 15.1 versions prior to 15.1R6-S2, 15.1R7;
  • 16.1 versions prior to 16.1R5-S1, 16.1R6;
  • 16.2 versions prior to 16.2R2-S2, 16.2R3;
  • 17.1 versions prior to 17.1R2-S5, 17.1R3;
  • 17.2 versions prior to 17.2R2.

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

This issue was seen in a production network.

This issue has been assigned CVE-2018-0006.
 

Solution:
The following software releases have been updated to resolve this specific issue: 15.1R6-S2, 15.1R7, 16.1R5-S1, 16.1R6, 16.2R2-S2, 16.2R3, 17.1R2-S5*, 17.1R3*, 17.2R2, 17.3R1, 17.4R1, and all subsequent releases.
*pending release

This issue is being tracked as PRs 1284213 and 1268129 which are 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:
Since this issue is specific to auto-sense or dynamic VLANs, utilizing a static VLAN model will mitigate this issue.
 
Implementation:
Software Releases, patches and updates are available at https://www.juniper.net/support/downloads/.
 
Modification History:
2018-01-10: Initial publication
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Related Links:
CVSS Score:
6.5 (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Risk Level:
Medium
Risk Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."