Avira Internet Security contains an improper link resolution vulnerability in the Software Updater component. During the update process, a privileged service running as SYSTEM deletes a file under C:\\ProgramData without validating whether the path resolves through a symbolic link or reparse point. A local attacker can create a malicious link to redirect the delete operation to an arbitrary file, resulting in deletion of attacker-chosen files with SYSTEM privileges.
This may lead to local privilege escalation, denial of service, or system integrity compromise depending on the targeted file and operating system configuration.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://blog.quarkslab.com/avira-deserialize-delete-and-escalate-the-proper-way…
disclosure@vulncheck.com
https://support.avira.com/hc/en-us/articles/360010656158-Current-Avira-versions
disclosure@vulncheck.com
https://www.avira.com/en/internet-security
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/avira-internet-security-arbitrary-file-del…
disclosure@vulncheck.com