2016-04 Security Bulletin: Junos: Manipulating TCP timestamps can lead to resource exhaustion denial of service (CVE-2016-1269)Product Affected:This issue can affect any product or platform running Junos OS.
Problem:By manipulating TCP timestamps within a TCP session to a reachable listening port, it may be possible for an attacker to trigger a persistent buffer/socket resource exhaustion denial of service DoS attack. Normally, a networked device will time out a session after a number of unsuccessful retransmission events, occurring at increasing intervals. However, in this case, a crafted sequence of TCP packets will cause the device to not try to retransmit, allowing the attacker to create sockets that will be long-lived without the need to maintain state on them.This issue was found during internal product security testing.Juniper SIRT is not aware of any malicious exploitation of this vulnerability.No other Juniper Networks products or platforms are affected by this issue.This issue has been assigned CVE-2016-1269.
Solution:The following software releases have been updated to resolve this specific issue: Junos OS 12.1X44-D60, 12.1X46-D40, 12.1X47-D30, 12.3R11, 12.3X48-D20, 13.2R9, 13.2X51-D39, 13.2X51-D40, 13.3R8, 14.1R6, 14.1X53-D30, 14.2R4-S1, 14.2R5, 15.1R2, 15.1X49-D30, 16.1R1, and all subsequent releases.This issue is being tracked as PR 1073571 and is visible on the Customer Support website.KB16765 – “In which releases are vulnerabilities fixed?” describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
Workaround:Use access lists or firewall filters to limit access to the router via TCP only from trusted hosts.In addition to the recommendations listed above, it is good security practice to limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit all administrative access to the router only from trusted, administrative networks or hosts.
Implementation:How to obtain fixed software:Security vulnerabilities in Junos are fixed in the next available Maintenance Release of each supported Junos version.
In some cases, a Maintenance Release is not planned to be available in an appropriate time-frame.
For these cases, Service Releases are made available in order to be more timely.
Security Advisory and Security Notices will indicate which Maintenance and Service Releases contain fixes for the issues described. Upon request to JTAC, customers will be provided download instructions for a Service Release.
Although Juniper does not provide formal Release Note documentation for a Service Release, a list of “PRs fixed” can be provided on request.Modification History:
2016-04-13: Initial publication
Related Links:CVSS Score:7.5 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
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.”