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Vulnerability Alert

Cisco IOS Software IPv6 Virtual Fragmentation Reassembly Denial of Service Vulnerability

 
Threat Type:CWE-362: Race Conditions
IntelliShield ID:30697
Version:1
First Published:2013 September 25 16:28 GMT
Last Published:2013 September 25 16:28 GMT
Port: Not available
CVE:CVE-2013-5474
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:7.8 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:6.4
Related Resources:
View related Security AdvisoryView related Event Response
 
 
Version Summary:Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
 
 
Description
A vulnerability in the implementation of the virtual fragmentation reassembly (VFR) feature for IP version 6 (IPv6) in Cisco IOS Software could allow an unauthenticated, remote attacker to cause an affected device to hang or reload, resulting in a denial of service (DoS) condition.

The vulnerability is due to a race condition while accessing the reassembly queue for IPv6 fragments. An attacker could exploit this vulnerability by sending a crafted stream of valid IPv6 fragments. Repeated exploitation may result in a sustained DoS condition.

Cisco confirmed the vulnerability in a security advisory and released software updates.
 
Warning Indicators
Cisco devices that are running an affected Cisco IOS Software release are vulnerable when the IPv6 VFR feature has been enabled.

Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The "Vendor Announcements" section of this alert contains a link to the advisory.
 
IntelliShield Analysis
To exploit this vulnerability, the attacker would need to send a crafted stream of valid IPv6 fragments to the targeted system. To achieve this objective, the attacker may need to access trusted, internal network resources. This access requirement reduces the likelihood of a successful exploit.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
 
Vendor Announcements
Cisco has released a security advisory for Cisco bug ID CSCud64812 at the following link: cisco-sa-20130925-ipv6vfr
 
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause an affected device to hang or reload, resulting in a DoS condition.
 
Technical Information
The vulnerability is due to a race condition that may occur while accessing the reassembly queue for IPv6 fragments.

An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted stream of valid IPv6 fragments to a targeted device. Processing the fragments could cause an affected device to hang or reload, resulting in a DoS condition. Repeated exploitation may result in a sustained DoS condition.
 
Safeguards
Administrators are advised to apply the appropriate updates.

It is critical to prevent unauthorized direct communication to network devices. Restrict network traffic destined for the network infrastructure to protect against reconnaissance and DoS attacks. For configuration details, see Protecting Your Core: Infrastructure Protection Access Control Lists.

Prevent disruption of communication between devices by reducing the impact of attacks that may directly affect the CPU performance of the individual devices. For control plane hardening best practices, see Cisco Guide to Harden Cisco IOS Devices.

To mitigate DoS attacks, apply hardware rate limiter features to limit packets that require CPU processing. See vendor documentation for specific configuration instructions. For hardware rate limiting configuration details, see Cisco Catalyst 6500 Denial of Service (DoS) Protection Configuration Guide.

Administrators are advised to monitor affected systems.
 
Patches/Software
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com.
 
Alert History
 
Initial Release


Product Sets
 
The security vulnerability applies to the following combinations of products.

Primary Products:
CiscoIOS 12.3T 12.3(7)T, 12.3(7)T1, 12.3(7)T10, 12.3(7)T11, 12.3(7)T12, 12.3(7)T2, 12.3(7)T3, 12.3(7)T4, 12.3(7)T6, 12.3(7)T7, 12.3(7)T8, 12.3(7)T9, 12.3(8)T, 12.3(8)T1, 12.3(8)T10, 12.3(8)T11, 12.3(8)T2, 12.3(8)T3, 12.3(8)T4, 12.3(8)T5, 12.3(8)T6, 12.3(8)T7, 12.3(8)T8, 12.3(8)T9, 12.3(11)T, 12.3(11)T1, 12.3(11)T10, 12.3(11)T11, 12.3(11)T12, 12.3(11)T2, 12.3(11)T2a, 12.3(11)T3, 12.3(11)T4, 12.3(11)T5, 12.3(11)T6, 12.3(11)T7, 12.3(11)T8, 12.3(11)T9, 12.3(14)T, 12.3(14)T1, 12.3(14)T2, 12.3(14)T3, 12.3(14)T4, 12.3(14)T5, 12.3(14)T6, 12.3(14)T7 | 12.3XG 12.3(4)XG, 12.3(4)XG1, 12.3(4)XG2, 12.3(4)XG3, 12.3(4)XG4, 12.3(4)XG5 | 12.3XH 12.3(4)XH, 12.3(4)XH1 | 12.3XK 12.3(4)XK, 12.3(4)XK1, 12.3(4)XK2, 12.3(4)XK3, 12.3(4)XK4 | 12.3XL 12.3(7)XL, 12.3(11)XL, 12.3(11)XL1, 12.3(11)XL2, 12.3(11)XL3 | 12.3XQ 12.3(4)XQ, 12.3(4)XQ1 | 12.3XR 12.3(7)XR, 12.3(7)XR1, 12.3(7)XR2, 12.3(7)XR3, 12.3(7)XR4, 12.3(7)XR5, 12.3(7)XR6, 12.3(7)XR7 | 12.3XS 12.3(7)XS, 12.3(7)XS1, 12.3(7)XS2 | 12.3XX 12.3(8)XX, 12.3(8)XX1, 12.3(8)XX2e | 12.3YA 12.3(8)YA, 12.3(8)YA1 | 12.3YC 12.3(8)YC, 12.3(8)YC1, 12.3(8)YC2, 12.3(8)YC3 | 12.3YD 12.3(8)YD, 12.3(8)YD1 | 12.3YG 12.3(8)YG, 12.3(8)YG1, 12.3(8)YG2, 12.3(8)YG3, 12.3(8)YG4, 12.3(8)YG5, 12.3(8)YG6, 12.3(8)YG7 | 12.3YH 12.3(8)YH | 12.3YI 12.3(8)YI, 12.3(8)YI1, 12.3(8)YI2, 12.3(8)YI3 | 12.3YK 12.3(11)YK, 12.3(11)YK1, 12.3(11)YK2, 12.3(11)YK3 | 12.3YM 12.3(14)YM1, 12.3(14)YM10, 12.3(14)YM11, 12.3(14)YM12, 12.3(14)YM13, 12.3(14)YM2, 12.3(14)YM3, 12.3(14)YM4, 12.3(14)YM5, 12.3(14)YM6, 12.3(14)YM7, 12.3(14)YM8, 12.3(14)YM9 | 12.3YN 12.3(11)YN | 12.3YS 12.3(11)YS, 12.3(11)YS1, 12.3(11)YS2 | 12.3YT 12.3(14)YT, 12.3(14)YT1 | 12.3YZ 12.3(11)YZ, 12.3(11)YZ1, 12.3(11)YZ2 | 12.3ZA 12.3(8)ZA, 12.3(8)ZA1 | 12.3ZB 12.3(11)ZB, 12.3(11)ZB1, 12.3(11)ZB2 | 12.4 12.4(1), 12.4(1a), 12.4(1b), 12.4(1c), 12.4(3), 12.4(3a), 12.4(3b), 12.4(3c), 12.4(3d), 12.4(3e), 12.4(3f), 12.4(3g), 12.4(3h), 12.4(3i), 12.4(3j), 12.4(5), 12.4(5a), 12.4(5b), 12.4(5c), 12.4(7), 12.4(7a), 12.4(7b), 12.4(7c), 12.4(7d), 12.4(7e), 12.4(7f), 12.4(7g), 12.4(7h), 12.4(8), 12.4(8a), 12.4(8b), 12.4(8c), 12.4(8d), 12.4(10), 12.4(10a), 12.4(10b), 12.4(10c), 12.4(12), 12.4(12a), 12.4(12b), 12.4(12c), 12.4(13), 12.4(13a), 12.4(13b), 12.4(13c), 12.4(13d), 12.4(13e), 12.4(13f), 12.4(16), 12.4(16a), 12.4(16b), 12.4(17), 12.4(17a), 12.4(17b), 12.4(18), 12.4(18a), 12.4(18b), 12.4(18c), 12.4(18d), 12.4(18e), 12.4(19), 12.4(21), 12.4(21a), 12.4(23), 12.4(23a), 12.4(23b), 12.4(23c), 12.4(23d), 12.4(23e), 12.4(25), 12.4(25a), 12.4(25b), 12.4(25c), 12.4(25d), 12.4(25e), 12.4(25f), 12.4(25g) | 12.4GC 12.4(22)GC1, 12.4(22)GC1a, 12.4(24)GC1, 12.4(24)GC3, 12.4(24)GC3a, 12.4(24)GC4, 12.4(24)GC5 | 12.4M 12.4(5a)M0, 12.4(21a)M1, 12.4(23b)M1 | 12.4MDA 12.4(24)MDA, 12.4(24)MDA1, 12.4(24)MDA10, 12.4(24)MDA11, 12.4(24)MDA12, 12.4(24)MDA13, 12.4(24)MDA2, 12.4(24)MDA3, 12.4(24)MDA4, 12.4(24)MDA5, 12.4(24)MDA6, 12.4(24)MDA7, 12.4(24)MDA8, 12.4(24)MDA9 | 12.4MDB 12.4(24)MDB, 12.4(24)MDB1, 12.4(24)MDB10, 12.4(24)MDB11, 12.4(24)MDB12, 12.4(24)MDB13, 12.4(24)MDB14, 12.4(24)MDB3, 12.4(24)MDB4, 12.4(24)MDB5, 12.4(24)MDB5a, 12.4(24)MDB6, 12.4(24)MDB7, 12.4(24)MDB8, 12.4(24)MDB9 | 12.4MR 12.4(16)MR1, 12.4(16)MR2, 12.4(19)MR, 12.4(19)MR1, 12.4(19)MR2, 12.4(19)MR3, 12.4(20)MR, 12.4(20)MR2 | 12.4MRA 12.4(20)MRA, 12.4(20)MRA1 | 12.4MRB 12.4(20)MRB, 12.4(20)MRB1 | 12.4T 12.4(2)T, 12.4(2)T1, 12.4(2)T2, 12.4(2)T3, 12.4(2)T4, 12.4(2)T5, 12.4(2)T6, 12.4(4)T, 12.4(4)T1, 12.4(4)T2, 12.4(4)T3, 12.4(4)T4, 12.4(4)T5, 12.4(4)T6, 12.4(4)T7, 12.4(4)T8, 12.4(6)T, 12.4(6)T1, 12.4(6)T10, 12.4(6)T11, 12.4(6)T12, 12.4(6)T2, 12.4(6)T3, 12.4(6)T4, 12.4(6)T5, 12.4(6)T5a, 12.4(6)T5b, 12.4(6)T5c, 12.4(6)T5e, 12.4(6)T5f, 12.4(6)T6, 12.4(6)T7, 12.4(6)T8, 12.4(6)T9, 12.4(9)T, 12.4(9)T0a, 12.4(9)T1, 12.4(9)T2, 12.4(9)T3, 12.4(9)T4, 12.4(9)T5, 12.4(9)T6, 12.4(9)T7, 12.4(11)T, 12.4(11)T1, 12.4(11)T2, 12.4(11)T3, 12.4(11)T4, 12.4(15)T, 12.4(15)T1, 12.4(15)T10, 12.4(15)T11, 12.4(15)T12, 12.4(15)T13, 12.4(15)T13b, 12.4(15)T14, 12.4(15)T15, 12.4(15)T16, 12.4(15)T17, 12.4(15)T2, 12.4(15)T3, 12.4(15)T4, 12.4(15)T5, 12.4(15)T6, 12.4(15)T6a, 12.4(15)T7, 12.4(15)T8, 12.4(15)T9, 12.4(20)T, 12.4(20)T1, 12.4(20)T2, 12.4(20)T3, 12.4(20)T4, 12.4(20)T5, 12.4(20)T5a, 12.4(20)T6, 12.4(22)T, 12.4(22)T1, 12.4(22)T2, 12.4(22)T3, 12.4(22)T4, 12.4(22)T5, 12.4(24)T, 12.4(24)T1, 12.4(24)T2, 12.4(24)T3, 12.4(24)T3c, 12.4(24)T3e, 12.4(24)T3f, 12.4(24)T31f, 12.4(24)T3g, 12.4(24)T32f, 12.4(24)T33f, 12.4(24)T34f, 12.4(24)T35c, 12.4(24)T35f, 12.4(24)T4, 12.4(24)T4a, 12.4(24)T4b, 12.4(24)T4c, 12.4(24)T4d, 12.4(24)T4e, 12.4(24)T4f, 12.4(24)T4g, 12.4(24)T4h, 12.4(24)T4i, 12.4(24)T4j, 12.4(24)T4k, 12.4(24)T4l, 12.4(24)T4m, 12.4(24)T4n, 12.4(24)T5, 12.4(24)T6, 12.4(24)T7, 12.4(24)T8, 12.4(24)T9 | 12.4XA 12.4(2)XA, 12.4(2)XA1, 12.4(2)XA2 | 12.4XC 12.4(4)XC, 12.4(4)XC1, 12.4(4)XC2, 12.4(4)XC3, 12.4(4)XC4, 12.4(4)XC5, 12.4(4)XC6, 12.4(4)XC7 | 12.4XD 12.4(4)XD, 12.4(4)XD1, 12.4(4)XD10, 12.4(4)XD11, 12.4(4)XD12, 12.4(4)XD2, 12.4(4)XD3, 12.4(4)XD4, 12.4(4)XD5, 12.4(4)XD6, 12.4(4)XD7, 12.4(4)XD8, 12.4(4)XD9 | 12.4XE 12.4(6)XE, 12.4(6)XE1, 12.4(6)XE2, 12.4(6)XE3 | 12.4XF 12.4(15)XF | 12.4XJ 12.4(11)XJ, 12.4(11)XJ1, 12.4(11)XJ2, 12.4(11)XJ3, 12.4(11)XJ4, 12.4(11)XJ5, 12.4(11)XJ6 | 12.4XK 12.4(14)XK | 12.4XQ 12.4(15)XQ, 12.4(15)XQ1, 12.4(15)XQ2, 12.4(15)XQ2a, 12.4(15)XQ2b, 12.4(15)XQ2c, 12.4(15)XQ2d, 12.4(15)XQ3, 12.4(15)XQ4, 12.4(15)XQ5, 12.4(15)XQ6, 12.4(15)XQ7, 12.4(15)XQ8 | 12.4XR 12.4(15)XR, 12.4(15)XR1, 12.4(15)XR10, 12.4(15)XR2, 12.4(15)XR3, 12.4(15)XR4, 12.4(15)XR5, 12.4(15)XR6, 12.4(15)XR7, 12.4(15)XR8, 12.4(15)XR9, 12.4(22)XR, 12.4(22)XR1, 12.4(22)XR10, 12.4(22)XR11, 12.4(22)XR12, 12.4(22)XR2, 12.4(22)XR3, 12.4(22)XR4, 12.4(22)XR5, 12.4(22)XR6, 12.4(22)XR7, 12.4(22)XR8, 12.4(22)XR9 | 12.4XT 12.4(6)XT, 12.4(6)XT1, 12.4(6)XT2 | 12.4XV 12.4(11)XV, 12.4(11)XV1 | 12.4XW 12.4(11)XW, 12.4(11)XW1, 12.4(11)XW10, 12.4(11)XW2, 12.4(11)XW3, 12.4(11)XW4, 12.4(11)XW5, 12.4(11)XW6, 12.4(11)XW7, 12.4(11)XW8, 12.4(11)XW9 | 12.4XY 12.4(15)XY, 12.4(15)XY1, 12.4(15)XY2, 12.4(15)XY3, 12.4(15)XY4, 12.4(15)XY5 | 12.4XZ 12.4(15)XZ, 12.4(15)XZ1, 12.4(15)XZ2 | 12.4YA 12.4(20)YA, 12.4(20)YA1, 12.4(20)YA2, 12.4(20)YA3 | 12.4YB 12.4(22)YB, 12.4(22)YB1, 12.4(22)YB4, 12.4(22)YB5, 12.4(22)YB6, 12.4(22)YB7, 12.4(22)YB8 | 12.4YD 12.4(22)YD, 12.4(22)YD1, 12.4(22)YD2, 12.4(22)YD3, 12.4(22)YD4 | 12.4YE 12.4(22)YE, 12.4(22)YE1, 12.4(22)YE2, 12.4(22)YE3, 12.4(22)YE4, 12.4(22)YE5, 12.4(22)YE6, 12.4(24)YE, 12.4(24)YE1, 12.4(24)YE2, 12.4(24)YE3, 12.4(24)YE3a, 12.4(24)YE3b, 12.4(24)YE3c, 12.4(24)YE3d, 12.4(24)YE3e, 12.4(24)YE4, 12.4(24)YE5, 12.4(24)YE6, 12.4(24)YE7 | 12.4YS 12.4(24)YS, 12.4(24)YS1 | 15.0M 15.0(1)M, 15.0(1)M1, 15.0(1)M10, 15.0(1)M2, 15.0(1)M3, 15.0(1)M4, 15.0(1)M5, 15.0(1)M6, 15.0(1)M6a, 15.0(1)M7, 15.0(1)M8, 15.0(1)M9 | 15.0XA 15.0(1)XA, 15.0(1)XA1, 15.0(1)XA2, 15.0(1)XA3, 15.0(1)XA4, 15.0(1)XA5 | 15.1GC 15.1(2)GC, 15.1(2)GC1, 15.1(2)GC2, 15.1(4)GC, 15.1(4)GC1 | 15.1M 15.1(4)M, 15.1(4)M0a, 15.1(4)M0b, 15.1(4)M1, 15.1(4)M2, 15.1(4)M3, 15.1(4)M3a, 15.1(4)M4, 15.1(4)M5, 15.1(4)M6 | 15.1T 15.1(1)T, 15.1(1)T1, 15.1(1)T2, 15.1(1)T3, 15.1(1)T4, 15.1(1)T5, 15.1(2)T, 15.1(2)T0a, 15.1(2)T1, 15.1(2)T2, 15.1(2)T2a, 15.1(2)T3, 15.1(2)T4, 15.1(2)T5, 15.1(3)T, 15.1(3)T1, 15.1(3)T2, 15.1(3)T3, 15.1(3)T4 | 15.1XB 15.1(1)XB, 15.1(1)XB1, 15.1(1)XB2, 15.1(1)XB3, 15.1(4)XB4, 15.1(4)XB5, 15.1(4)XB5a, 15.1(4)XB6, 15.1(4)XB7, 15.1(4)XB8a | 15.2GC 15.2(1)GC, 15.2(1)GC1, 15.2(1)GC2, 15.2(2)GC, 15.2(3)GC | 15.2GCA 15.2(3)GCA | 15.2M 15.2(4)M, 15.2(4)M1, 15.2(4)M2, 15.2(4)M3 | 15.2T 15.2(1)T, 15.2(1)T1, 15.2(1)T2, 15.2(1)T3, 15.2(1)T3a, 15.2(1)T4, 15.2(2)T, 15.2(2)T1, 15.2(2)T2, 15.2(2)T3, 15.2(3)T, 15.2(3)T1, 15.2(3)T2 | 15.2XA 15.2(3)XA | 15.2XB 15.2(4)XB10 | 15.3T 15.3(1)T

Associated Products:
N/A




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