Multiple vulnerabilities in Avast Antivirus

Published: 2019-11-05

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2019-18653 CVE-2019-11230
CWE-ID	CWE-79 CWE-59
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software Subscribe	Avast Antivirus Client/Desktop applications / Antivirus software/Personal firewalls
Vendor	Avast Software s.r.o.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Cross-site scripting

EUVDB-ID: #VU22524

Risk: Low

CVSSv3.1: 5.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-18653

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

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

External links

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

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.

2) Link following

EUVDB-ID: #VU22526

Risk: Low

CVSSv3.1: 2 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-11230

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to the . A local authenticated administrator can replace the "LogsUpdate.log" file with a symlink, trick the product into renaming arbitrary files and cause a denial of service on the target system.

This defect can be exploited to rename a critical product file (e.g., AvastSvc.exe), causing the product to fail to start on the next system restart.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Avast Antivirus: 12.1.2272 - 2016.11.1.2262

External links

http://www.mcerlane.co.uk/CVE-2019-11230/

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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