Intego Personal Backup, a macOS backup utility that allows users to create scheduled backups and bootable system clones, contains a local privilege escalation vulnerability. Backup task definitions are stored in a location writable by non-privileged users while being processed with elevated privileges. By crafting a malicious serialized task file, a local attacker can trigger arbitrary file writes to sensitive system locations, leading to privilege escalation to root.
Weakness
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
Potential Mitigations
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/132.html
- https://cwe.mitre.org/data/definitions/17.html
- https://cwe.mitre.org/data/definitions/35.html
- https://cwe.mitre.org/data/definitions/76.html
References
- https://blog.quarkslab.com/intego_lpe_macos_1.html
- https://integosupport.zendesk.com/hc/en-us/articles/40945636077467-Personal-Backup-X9-Release-Notes
- https://www.intego.com/
- https://www.intego.com/bootable-mac-backups
- https://www.vulncheck.com/advisories/intego-personal-backup-task-file-privilege-escalation