Juniper Junos OS Denial Of Service Vulnerabilities
23 Sep. 2015
Juniper Junos OS 12.1X44 before 12.1X44-D50, 12.1X46 before 12.1X46-D35, 12.1X47 before 12.1X47-D25, 12.3 before 12.3R9, 12.3X48 before 12.3X48-D15, 13.2 before 13.2R7, 13.2X51 before 13.2X51-D35, 13.2X52 before 13.2X52-D25, 13.3 before 13.3R6, 14.1R3 before 14.1R3-S2, 14.1 before 14.1R4, 14.1X53 before 14.1X53-D12, 14.1X53 before 14.1X53-D16, 14.1X55 before 14.1X55-D25, 14.2 before 14.2R2, and 15.1 before 15.1R1 allows remote attackers to cause a denial of service (mbuf and connection consumption and restart) via a large number of requests that trigger a TCP connection to move to the LAST_ACK state when there is more data to send.
* Juniper Junos OS before 15.1R1
* Juniper Junos OS after 15.1R1
TCP connections transitioning to the LAST_ACK state can become permanently stuck due to mishandling of protocol state in certain situations, which in turn can lead to accumulated consumption and eventual exhaustion of system resources, such as mbufs and sockets. An attacker who can repeatedly establish TCP connections to a victim system (for instance, a Web server) could create many TCP connections that are stuck in LAST_ACK state and cause resource exhaustion, resulting in adenial of service condition. This may also happen in normal operation where no intentional attack is conducted, but an attacker who can sendspecifically crafted packets can trigger this more reliably.