Vulnerability · Published Mar 29, 2021 · Assigned by zdi

CVE-2021-27241

Medium 6.1

In plain English

A medium-severity security flaw in Premium Security from Avast. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities).

Severity (CVSS 3.0)6.1Medium

Exploit odds (30 days)0.3%top 80.6% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

This vulnerability allows local attackers to delete arbitrary directories on affected installations of Avast Premium Security 20.8.2429 (Build 20.8.5653.561). An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the AvastSvc.exe module. By creating a directory junction, an attacker can abuse the service to delete a directory. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-12082.

Affected products (as reported)

Vendor	Product	Versions
Avast	Premium Security	20.8.2429 (Build 20.8.5653.561)

Weakness: CWE-59 · Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

References

https://www.zerodayinitiative.com/advisories/ZDI-21-208/ x_refsource_MISC