#VU22524 Cross-site scripting in Avast Antivirus - CVE-2019-18653

Vulnerability identifier: #VU22524

Vulnerability risk: Low

CVSSv4.0: 1.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P/U:Clear]

CVE-ID: CVE-2019-18653

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Avast Antivirus
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: Avast Software s.r.o.

Description

The vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists in the Network Notification Popup due to insufficient sanitization of user-supplied data passed via an SSID Name. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Avast Antivirus: 19.3.2369

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External links
https://firstsight.me/2019/10/5000-usd-xss-issue-at-avast-desktop-antivirus-for-windows-yes-desktop/
https://medium.com/@YoKoKho/5-000-usd-xss-issue-at-avast-desktop-antivirus-for-windows-yes-desktop-1e99375f0968

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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. However, proof of concept for this vulnerability is available.