Vulnerability identifier: #VU6311

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-6609

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Adaptive Security Appliance (ASA)
Hardware solutions / Security hardware applicances
Cisco ASA 1000V Cloud Firewall
Hardware solutions / Security hardware applicances
Cisco ASA 5500
Hardware solutions / Security hardware applicances
Cisco ASA 5500-X Series
Hardware solutions / Security hardware applicances
Cisco 7600 Series ASA Services Module
Hardware solutions / Security hardware applicances
Cisco Firepower 9300 ASA Security Module
Hardware solutions / Security hardware applicances
Cisco ISA 3000 Industrial Security Appliance
Hardware solutions / Security hardware applicances
Cisco Adaptive Security Virtual Appliance (ASAv)
Server applications / Virtualization software

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to cause denial of service vulnerability.

The vulnerability exists due to improper parsing of malformed IPsec packets. A remote authenticated attacker can send specially crafted IPsec packets to the affected system and perform a denial of service (DoS) attack. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. An attacker needs to establish a valid IPsec tunnel before exploiting this vulnerability.

Mitigation
Install updates from vendor's website:

Prior to 9.0	Affected, migrate to 9.1(7.8) or later
9.0	Affected, migrate to 9.1(7.8) or later
9.1	9.1(7.8) or later
9.2	9.2(4.15) or later
9.3	Affected, migrate to 9.4(4) or later
9.4	9.4(4) or later
9.5	9.5(3.2) or later
9.6	9.6(2) or later

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): 9.0 - 9.6.1

Cisco ASA 1000V Cloud Firewall : 8.7.1

Cisco ASA 5500: All versions

Cisco ASA 5500-X Series: All versions

Cisco 7600 Series ASA Services Module: All versions

Cisco Adaptive Security Virtual Appliance (ASAv): All versions

Cisco Firepower 9300 ASA Security Module: All versions

Cisco ISA 3000 Industrial Security Appliance: All versions

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170419-asa-ipsec

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.