Avast and AVG Antivirus: Improper Privilege Management
CVE-2022-4173 is a high-severity improper privilege management vulnerability in Avast and AVG Antivirus from NortonLifeLock, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Avast and AVG Antivirus versions: 20.5 through 22.9. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.75% chance of exploitation within 30 days, higher than 56% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Avast and AVG Antivirus you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on support.norton.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| NortonLifeLock | Avast and AVG Antivirus | 20.5 through 22.9 | Not stated |
| Avast | Avast | 20.5 through 22.9 | Not stated |
| Avast | Avg Antivirus | 20.5 through 22.9 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.3 | High | CNA (nortonlifelock.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A vulnerability within the malware removal functionality of Avast and AVG Antivirus allowed an attacker with write access to the filesystem, to escalate his privileges in certain scenarios. The issue was fixed with Avast and AVG Antivirus version 22.10.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Privilege Management
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.
More Improper Privilege Management vulnerabilities (CWE-269)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- support.norton.com/sp/static/external/tools/security-advisories.htmlThird Party Advisory
Recent Improper Privilege Management vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 9.9 Critical severity
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