Vulnerability identifier: #VU15358

Vulnerability 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-2018-15397

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Adaptive Security Appliance (ASA)
Hardware solutions / Security hardware applicances

Vendor: Cisco Systems, Inc

Description
The vulnerability allows a remote unauthenticated attacker to cause DoS condition on the target system.

The weakness exists in the implementation of Traffic Flow Confidentiality (TFC) over IPsec functionality due to an error during renegotiating of the encryption key for an IPsec tunnel when certain TFC traffic is in flight. A remote attacker can send a malicious stream of TFC traffic through an established IPsec tunnel and cause a daemon process on the affected device to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): 9.4.4

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181003-asa-ipsec-dos

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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.