AV:N/AC:M/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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A vulnerability in the processing of IPv4 packets that require Network Address Translation (NAT) and Multiprotocol Label Switching (MPLS) services of Cisco IOS XE Software for Cisco ASR 1000 Series, Cisco ISR 4300 Series, Cisco ISR 4400 Series, and Cisco Cloud Services 1000v Series Routers could allow an unauthenticated, remote attacker to cause a reload of the affected device.
The vulnerability is due to improper processing of IPv4 packets that require NAT and MPLS processing. An attacker could exploit this vulnerability by sending an IPv4 packet to be processed by a Cisco IOS XE device configured to perform NAT and MPLS services. A successful exploit could allow the attacker to cause a reload of the affected device.
Cisco has released software updates that address these vulnerabilities. There are no workarounds to mitigate this vulnerability.
This advisory is available at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150923-iosxe
Note: The September 23, 2015, release of the Cisco IOS and IOS XE Software Security Advisory bundled publication includes three Cisco Security Advisories. All the advisories address vulnerabilities in Cisco IOS Software and Cisco IOS XE Software. Individual publication links are in Cisco Event Response: September 2015 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication at the following link:http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep15.html
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Vulnerable Products
Cisco IOS XE Software contains a vulnerability that could cause an affected device to reload when processing IPv4 packets that require NAT and MPLS services.
This vulnerability can be exploited only with transit IPv4 packets. Packets destined to an affected device or IPv6 packets cannot be used to trigger this vulnerability. NAT and MPLS services are not enabled by default.
To determine whether NAT has been enabled in the Cisco IOS XE Software configuration, the ip nat inside or ip nat outside commands must be present in different interfaces and at least one ip nat global configuration command must be present in the configuration.
The show running-config | include ip nat command can be used to determine whether NAT is present in the configuration, as illustrated in the following example of a vulnerable configuration:asr1000#show running-config | include ip nat
ip nat inside
ip nat outside
ip nat pool test 192.168.0.1 192.168.0.254 netmask 255.255.255.0
ip nat outside source list 1 pool test
To determine whether MPLS has been enabled in the Cisco IOS XE Software configuration, the mpls ip commands must be present in at least one interface.
The show running-config | include mpls ip command can be used to determine whether MPLS is present in the configuration, as illustrated in the following example of a vulnerable configuration:
asr1000#show running-config | include mpls ip
mpls ip
- Whether the mpls ip command is present on the same interface as the ip nat outside command in the configuration
- Whether the ip nat inside command is present in the configuration of another interface
asr1000# show running-config interface
!
interface GigabitEthernet0/0
no shutdown
ip address 10.86.194.60 255.255.254.0
ip nat inside
!
interface GigabitEthernet0/1
no shutdown
ip address 10.10.4.200 255.255.0.0
ip nat outside
mpls ip
!Products Confirmed Not Vulnerable
Cisco IOS Software is not affected by this vulnerability.
Cisco IOS XR Software is not affected by this vulnerability.
Cisco NX-OS Software is not affected by this vulnerability.
No other Cisco products are currently known to be affected by this vulnerability.
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A vulnerability in the processing of IPv4 packets that require Network Address Translation (NAT) and Multiprotocol Label Switching (MPLS) services of Cisco IOS XE Software for Cisco ASR 1000 Series, Cisco ISR 4300 Series, Cisco ISR 4400 Series, and Cisco Cloud Services 1000v Series Routers could allow an unauthenticated, remote attacker to cause a reload of the affected device.
The vulnerability is due to improper processing of IPv4 packets that require NAT and MPLS processing. An attacker could exploit this vulnerability by sending an IPv4 packet to be processed by a Cisco IOS XE device configured to perform NAT and MPLS services. A successful exploit could allow the attacker to cause a reload of the affected device.
To exploit this vulnerability, an IPv4 packet must arrive on interface configured with the ip nat inside command and be destined for outbound processing on an interface configured with the ip nat outside and mpls ip commands.
This vulnerability is documented in Cisco Bug ID CSCut96933 (registered customers only), and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2015-6282.
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There are no workarounds for this vulnerability.
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When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Alerts archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Cisco IOS XE Software
Cisco IOS XE Software is affected by the vulnerability described in this advisory.
For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to Cisco IOS XE 2 Release Notes and Cisco IOS XE 3S Release Notes.
Cisco IOS XE Software Release First Fixed Release for this Advisory First Fixed Release for
All Advisories in the
September 2015 Cisco IOS and IOS XE
Software Security Advisory
Bundled Publication
2.x.x Vulnerable, migrate to 3.10.6S or later.
Vulnerable; migrate to 3.10.6S or later. 3.x.xS Vulnerable, migrate to 3.10.6S or later.
Vulnerable; migrate to 3.10.6S or later.
3.10.xS 3.10.6S 3.10.6S 3.11.xS Vulnerable, migrate to 3.13.3S or later. Vulnerable; migrate to 3.13.3S or later. 3.12.xS Vulnerable, migrate to 3.13.3S or later. Vulnerable; migrate to 3.13.3S or later. 3.13.xS 3.13.3S 3.13.3S 3.14.xS
Vulnerable, migrate to 3.15.1S or later. Vulnerable; migrate to 3.15.1S or later. 3.15.xS
3.15.1S 3.15.1S 3.16.xS Not vulnerable Not vulnerable
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was found during the resolution of a support case.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Revision 1.0 2015-September-23 Initial public release.
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