Backblaze for Windows before 7.0.1.433 and Backblaze for macOS before 7.0.1.434 suffer from improper certificate validation in bztransmit helper due to hardcoded whitelist of strings in URLs where validation is disabled leading to possible remote code execution via client update functionality.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-8289
• https://hackerone.com/reports/818853
• https://github.com/geffner/CVE-2020-8289/blob/master/README.md
• https://www.backblaze.com/blog/backblaze-cloud-backup-release-7-0-1/
• https://youtu.be/W0THXbcX5V8
• http://seclists.org/fulldisclosure/2020/Dec/57
• http://seclists.org/fulldisclosure/2020/Dec/58