The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities.
The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload.
Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable.
There are workarounds that address these vulnerabilities.
The AAA service in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.1 through 3.18 and 16.2 allows remote attackers to cause a denial of service (device reload) via a failed SSH connection attempt that is mishandled during generation of an error-log message, aka Bug ID CSCuy87667.
The Zone-Based Firewall (ZBFW) functionality in Cisco IOS, possibly 15.4 and earlier, and IOS XE, possibly 3.13 and earlier, mishandles zone checking for existing sessions, which allows remote attackers to bypass intended resource-access restrictions via spoofed traffic that matches one of these sessions, aka Bug IDs CSCun94946 and CSCun96847.
The server IKEv1 implementation in Cisco IOS 12.2 through 12.4 and 15.0 through 15.6, IOS XE through 3.18S, IOS XR 4.3.x and 5.0.x through 5.2.x, and PIX before 7.0 allows remote attackers to obtain sensitive information from device memory via a Security Association (SA) negotiation request, aka Bug IDs CSCvb29204 and CSCvb36055 or BENIGNCERTAIN.
The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.
Cisco IOS XE 2.x and 3.x before 3.10.6S, 3.11.xS through 3.13.xS before 3.13.3S, and 3.14.xS through 3.15.xS before 3.15.1S allows remote attackers to cause a denial of service (device reload) via IPv4 packets that require NAT and MPLS actions, aka Bug ID CSCut96933.
Cisco IOS XE 2.1.0 through 2.2.3 and 2.3.0 on ASR 1000 devices, when NAT Application Layer Gateway is used, allows remote attackers to cause a denial of service (Embedded Services Processor crash) via a crafted H.323 packet, aka Bug ID CSCsx35393, CSCsx07094, and CSCsw93064.
Cisco IOS XE 2.1.0 through 2.4.3 and 2.5.0 on ASR 1000 devices, when NAT Application Layer Gateway is used, allows remote attackers to cause a denial of service (Embedded Services Processor crash) via a crafted SIP packet, aka Bug IDs CSCta74749 and CSCta77008.
Cisco IOS XE before 3.1.2S on ASR 1000 devices mishandles the automatic setup of Virtual Fragment Reassembly (VFR) by certain firewall and NAT components, which allows remote attackers to cause a denial of service (Embedded Services Processor crash) via crafted IP packets, aka Bug IDs CSCtf87624, CSCte93229, CSCtd19103, and CSCti63623.
Cisco IOS XE 2.x before 2.4.3 and 2.5.x before 2.5.1 on ASR 1000 devices allows remote attackers to cause a denial of service (Embedded Services Processor crash) via a crafted series of fragmented (1) IPv4 or (2) IPv6 packets, aka Bug ID CSCtd72617.