Hackers target Cisco ASA devices

 Researchers at Positive Technologies have published a proof-of-concept exploit for CVE-2020-3580. There are reports of researchers pursuing bug bounties using this exploit.

n October 21, 2021, Cisco released a security advisory and patches to address multiple cross-site scripting (XSS) vulnerabilities in its Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) software web services. In April, Cisco updated the advisory to account for an incomplete fix of CVE-2020-3581.

Shortly after, Mikhail Klyuchnikov, a researcher at Positive Technologies also tweeted that other researchers are chasing bug bounties for this vulnerability. Tenable has also received a report that attackers are exploiting CVE-2020-3580 in the wild.


All four vulnerabilities exist because Cisco ASA and FTD software web services do not sufficiently validate user-supplied inputs. To exploit any of these vulnerabilities, an attacker would need to convince “a user of the interface” to click on a specially crafted link. Successful exploitation would allow the attacker to execute arbitrary code within the interface and access sensitive, browser-based information.

These vulnerabilities affect only specific AnyConnect and WebVPN configurations:

Proof of concept

As mentioned earlier, there is a public PoC published by Positive Technologies on Twitter, which has gained significant attention.

Vendor response

Cisco has not issued any additional information or updates since the PoC was published.