A Boxcryptor audit shows no critical weaknesses in the software
More and more companies, self-employed and private customers are using Boxcryptor to protect sensitive data – primarily in the cloud. Boxcryptor ensures that nobody but authorized persons have access to the data. Cloud providers and their staff, as well as potential hackers are reliably excluded. The audit verified whether this protection is guaranteed.
During the audit, Kudelski was given access to the source code of Boxcryptor for Windows and to the internal documentation.
“All these components were logically correct and did not show any significant weakness under scrutiny. It is important to note that the codebase we audited was not showing any signs of malicious intent.”
The goal of the audit
The goal of the audit was to give all interested parties an indirect insight into the software so that they can be sure that no backdoors or security holes are found in the code.
Robert Freudenreich, CTO of Boxcryptor, about the benefits of an audit: “For private users, Boxcryptor is a means of digital self-defense against curious third parties, for companies and organizations a way to achieve true GDPR compliance and complete control over business data. With software that is so security relevant, it is understandable that users want to be sure that the software is flawless.”
The audit process started at the beginning of May with short communication lines to the developers and managers in the Boxcryptor team. If Kudelski had found a serious security vulnerability, they would not have held it back until the final report, but would have reported the problem immediately.
A problem rated as “medium”
The problem rated as medium is a part of the code that affects the connection to cloud providers using the WebDAV protocol. Theoretically, the operators of such cloud storage providers could have tried to inject code into Boxcryptor for Windows.
In practice, however, this code was never used by Boxcryptor, so there was no danger for Boxcryptor users at any time. In response to the audit, this redundant part of the code was removed.
Two problems classified as “low” and further observations
One problem classified as low concerns the user password: to protect users with insecure passwords, it was suggested that passwords be hashed even more frequently and that the minimum password length be increased, which we implemented immediately.
The second problem classified as low was theoretical and concerned the reading of the Boxcryptor configuration.