CERT Advisory CA-2002-03 describes a series of tests designed to determine the vulnerability of SNMP implementations. Juniper Networks has evaluated its software using the provided test suites, and has determined that, with one exception, the JUNOS Internet software is not vulnerable to any of the potential exploits. The only vulnerability found occurred when SNMP PDU tracing was enabled (snmp traceoptions flag pdu). With this trace flag enabled, certain invalid SNMP varbinds can cause the SNMP process to overflow a buffer and terminate. Although one could theoretically use this buffer overflow to gain root access to the router, no known exploit code exists.
Stricter checking and validation of all SNMP packets has been implemented in all JUNOS software released on or after January 5th, 2002.
Customers who are running affected JUNOS software released prior to January 5th, 2002, and who also have SNMP PDU tracing enabled, should update their software to a version released on or after January 5th, 2002. This software can be downloaded from the Juniper Networks web site at http://www.juniper/net/support/. As a work-around, customers can remove ýsnmp traceoptions flag pduý from the routerýs configuration.