#VU57800 Improper Handling of Unexpected Data Type in Cisco Firepower Threat Defense (FTD) and Snort - CVE-2021-40116

Vulnerability identifier: #VU57800

Vulnerability risk: High

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-40116

CWE-ID: CWE-241

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Firepower Threat Defense (FTD)
Hardware solutions / Security hardware applicances
Snort
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Cisco Systems, Inc
Sourcefire

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. A remote attacker can send a specially crafted IP packet and perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Cisco Firepower Threat Defense (FTD): 7.0.0

Snort: before 3.1.0.100

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External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-dos-RywH7ezM

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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.