Remote DoS when parsing DNS responses in Cisco ASA

1) Improper input validation

EUVDB-ID: #VU6312

Risk: Medium

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-6607

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

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

The vulnerability exists due to improper parsing of malformed DNS responses. A remote attacker can send trigger the device to send a DNS request to malicious DNS server, reply with specially crafted DNS response packet perform a denial of service (DoS) attack.

Successful exploitation of the vulnerability may allow an attacker to reload the affected device causing DoS conditions or corrupt local DNS cache information.

Mitigation

Install updates from vendor's website.

Prior to 9.01	Affected, migrate to 9.1(7.12) or later
9.01	Affected, migrate to 9.1(7.12) or later
9.1	9.1(7.12) or later
9.2	9.2(4.18) or later
9.31	Affected, migrate to 9.4(3.12) or later
9.4	9.4(3.12) or later
9.5	9.5(3.2) or later
9.6	9.6(2.2) or later
9.7	Not affected
9.8	Not affected

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): 9.0 - 9.6.2

Cisco ASA 1000V Cloud Firewall : 8.7.1

Cisco ASA 5500: All versions

Cisco ASA 5500-X Series: All versions

Cisco Catalyst 6500 Series ASA Services Module: 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

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170419-asa-dns

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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