Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured file policies on an affected system. The vulnerability is due to errors in how the Snort detection engine handles specific HTTP responses. An attacker could exploit this vulnerability by sending crafted HTTP packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured file policies and deliver a malicious payload to the protected network.

A vulnerability in the IPv6 DHCP (DHCPv6) client module of Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense (FTD) Software, Cisco IOS Software, and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation of DHCPv6 messages. An attacker could exploit this vulnerability by sending crafted DHCPv6 messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To successfully exploit this vulnerability, the attacker would need to either control the DHCPv6 server or be in a man-in-the-middle position.

Cisco IOS 12.4 contains multiple cross-site forgery vulnerabilities that allows remote attackers to execute arbitrary commands via (1) a certain "show privilege" command to the /level/15/exec/- URI, and (2) a certain "alias exec" command to the /level/15/exec/-/configure/http URI.

A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker who has administrative control of either a group member or a key server to execute arbitrary code on an affected device or cause the device to crash. This vulnerability is due to insufficient validation of attributes in the Group Domain of Interpretation (GDOI) and G-IKEv2 protocols of the GET VPN feature. An attacker could exploit this vulnerability by either compromising an installed key server or modifying the configuration of a group member to point to a key server that is controlled by the attacker. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a denial of service (DoS) condition. For more information, see the Details ["#details"] section of this advisory.

Multiple vulnerabilities in the Login Enhancements (Login Block) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a reload of an affected system, resulting in a denial of service (DoS) condition. These vulnerabilities affect Cisco devices that are running Cisco IOS Software Release 15.4(2)T, 15.4(3)M, or 15.4(2)CG and later. Cisco Bug IDs: CSCuy32360, CSCuz60599.

Multiple vulnerabilities in the Login Enhancements (Login Block) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a reload of an affected system, resulting in a denial of service (DoS) condition. These vulnerabilities affect Cisco devices that are running Cisco IOS Software Release 15.4(2)T, 15.4(3)M, or 15.4(2)CG and later. Cisco Bug IDs: CSCuy32360, CSCuz60599.

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software running on certain models of Cisco Catalyst Switches could allow an authenticated, remote attacker to cause a denial of service (DoS) condition, aka a GET MIB Object ID Denial of Service Vulnerability. The vulnerability is due to a condition that could occur when the affected software processes an SNMP read request that contains a request for the ciscoFlashMIB object ID (OID). An attacker could trigger this vulnerability by issuing an SNMP GET request for the ciscoFlashMIB OID on an affected device. A successful exploit could cause the affected device to restart due to a SYS-3-CPUHOG. This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS Software and are configured to use SNMP Version 2 (SNMPv2) or SNMP Version 3 (SNMPv3): Cisco Catalyst 2960-L Series Switches, Cisco Catalyst Digital Building Series Switches 8P, Cisco Catalyst Digital Building Series Switches 8U. Cisco Bug IDs: CSCvd89541.

A vulnerability in the Autonomic Networking feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause autonomic nodes of an affected system to reload, resulting in a denial of service (DoS) condition. More Information: CSCvd88936. Known Affected Releases: Denali-16.2.1 Denali-16.3.1.

A vulnerability in the Autonomic Networking Infrastructure (ANI) feature of Cisco IOS Software (15.4 through 15.6) and Cisco IOS XE Software (3.7 through 3.18, and 16) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incomplete input validation on certain crafted packets. An attacker could exploit this vulnerability by sending a crafted IPv6 packet to a device that is running a Cisco IOS Software or Cisco IOS XE Software release that supports the ANI feature. A device must meet two conditions to be affected by this vulnerability: (1) the device must be running a version of Cisco IOS Software or Cisco IOS XE Software that supports ANI (regardless of whether ANI is configured); and (2) the device must have a reachable IPv6 interface. An exploit could allow the attacker to cause the affected device to reload. Cisco Bug IDs: CSCvc42729.

A vulnerability in the Cisco IOS Software forwarding queue of Cisco 2960X and 3750X switches could allow an unauthenticated, adjacent attacker to cause a memory leak in the software forwarding queue that would eventually lead to a partial denial of service (DoS) condition. More Information: CSCva72252. Known Affected Releases: 15.2(2)E3 15.2(4)E1. Known Fixed Releases: 15.2(2)E6 15.2(4)E3 15.2(5)E1 15.2(5.3.28i)E1 15.2(6.0.49i)E 3.9(1)E.

A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability. The vulnerability exists due to changes in the implementation of the BGP MPLS-Based Ethernet VPN RFC (RFC 7432) draft between IOS XE software releases. When the BGP Inclusive Multicast Ethernet Tag Route or BGP EVPN MAC/IP Advertisement Route update packet is received, it could be possible that the IP address length field is miscalculated. An attacker could exploit this vulnerability by sending a crafted BGP packet to an affected device after the BGP session was established. An exploit could allow the attacker to cause the affected device to reload or corrupt the BGP routing table; either outcome would result in a DoS. The vulnerability may be triggered when the router receives a crafted BGP message from a peer on an existing BGP session. This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. If the device is not configured for EVPN, it is not vulnerable. Cisco Bug IDs: CSCui67191, CSCvg52875.

A vulnerability in the Virtual Private LAN Service (VPLS) code of Cisco IOS 15.0 through 15.4 for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, adjacent attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a denial of service (DoS) condition. The vulnerability is due to a memory management issue in the affected software. An attacker could exploit this vulnerability by creating a large number of VPLS-generated MAC entries in the MAC address table of an affected device. A successful exploit could allow the attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a DoS condition. This vulnerability affects Cisco Catalyst 6800 Series Switches that are running a vulnerable release of Cisco IOS Software and have a Cisco C6800-16P10G or C6800-16P10G-XL line card in use with Supervisor Engine 6T. To be vulnerable, the device must also be configured with VPLS and the C6800-16P10G or C6800-16P10G-XL line card needs to be the core-facing MPLS interfaces. Cisco Bug IDs: CSCva61927.

A vulnerability in the implementation of a protocol in Cisco Integrated Services Routers Generation 2 (ISR G2) Routers running Cisco IOS 15.0 through 15.6 could allow an unauthenticated, adjacent attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a misclassification of Ethernet frames. An attacker could exploit this vulnerability by sending a crafted Ethernet frame to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvc03809.

The IKE implementation in Cisco IOS 15.4(1)T and earlier and IOS XE allows remote attackers to cause a denial of service (security-association drop) via crafted Main Mode packets, aka Bug ID CSCun31021.

The packet driver in Cisco IOS allows remote attackers to cause a denial of service (device reload) via a series of (1) Virtual Switching Systems (VSS) or (2) Bidirectional Forwarding Detection (BFD) packets, aka Bug IDs CSCug41049 and CSCue61890.

The IP Device Tracking (IPDT) feature in Cisco IOS and IOS XE allows remote attackers to cause a denial of service (IPDT AVL corruption and device reload) via a crafted sequence of ARP packets, aka Bug ID CSCuh38133.

The SSL VPN implementation in Cisco IOS 15.3(1)T2 and earlier allows remote authenticated users to cause a denial of service (interface queue wedge) via crafted DTLS packets in an SSL session, aka Bug IDs CSCuh97409 and CSCud90568.

The MLDP implementation in Cisco IOS 15.3(3)S and earlier on 7600 routers, when many VRFs are configured, allows remote attackers to cause a denial of service (chunk corruption and device reload) by establishing many multicast flows, aka Bug ID CSCue22345.

The IPSec implementation in Cisco IOS allows remote attackers to cause a denial of service (MTU change and tunnel-session drop) via crafted ICMP packets, aka Bug ID CSCul29918.

Cross-site scripting (XSS) vulnerability in +webvpn+/index.html in WebVPN on the Cisco Adaptive Security Appliances (ASA) 5520 with software 7.2(4)30 and earlier 7.2 versions including 7.2(2)22, and 8.0(4)28 and earlier 8.0 versions, when clientless mode is enabled, allows remote attackers to inject arbitrary web script or HTML via the Host HTTP header.

The (1) Airline Product Set (aka ALPS), (2) Serial Tunnel Code (aka STUN), (3) Block Serial Tunnel Code (aka BSTUN), (4) Native Client Interface Architecture (NCIA) support, (5) Data-link switching (aka DLSw), (6) Remote Source-Route Bridging (RSRB), (7) Point to Point Tunneling Protocol (PPTP), (8) X.25 for Record Boundary Preservation (RBP), (9) X.25 over TCP (XOT), and (10) X.25 Routing features in Cisco IOS 12.2 and 12.4 allows remote attackers to cause a denial of service (device reload) via a series of crafted TCP packets.

Cross-site request forgery (CSRF) vulnerability in the HTTP server in Cisco IOS 12.4(23) allows remote attackers to execute arbitrary commands, as demonstrated by executing the hostname command with a level/15/configure/-/hostname request.

Multiple cross-site scripting (XSS) vulnerabilities in the HTTP server in Cisco IOS 12.4(23) allow remote attackers to inject arbitrary web script or HTML via the PATHINFO to the default URI under (1) level/15/exec/-/ or (2) exec/, a different vulnerability than CVE-2008-3821.

Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.

OpenSSL 0.9.6k allows remote attackers to cause a denial of service (crash via large recursion) via malformed ASN.1 sequences.

The web server for Cisco Aironet AP1x00 Series Wireless devices running certain versions of IOS 12.2 allow remote attackers to cause a denial of service (reload) via a malformed URL.

Cisco IOS 12.2 and earlier generates a "% Login invalid" message instead of prompting for a password when an invalid username is provided, which allows remote attackers to identify valid usernames on the system and conduct brute force password guessing, as reported for the Aironet Bridge.

The Service Assurance Agent (SAA) in Cisco IOS 12.0 through 12.2, aka Response Time Reporter (RTR), allows remote attackers to cause a denial of service (crash) via malformed RTR packets to port 1967.

The design of the Hot Standby Routing Protocol (HSRP), as implemented on Cisco IOS 12.1, when using IRPAS, allows remote attackers to cause a denial of service (CPU consumption) via a router with the same IP address as the interface on which HSRP is running, which causes a loop.

Cisco 2611 router running IOS 12.1(6.5), possibly an interim release, allows remote attackers to cause a denial of service via port scans such as (1) scanning all ports on a single host and (2) scanning a network of hosts for a single open port through the router. NOTE: the vendor could not reproduce this issue, saying that the original reporter was using an interim release of the software.