CVE-2020-28924 : Exploit Details and Defense Strategies

An issue was discovered in Rclone before 1.53.3 where weak passwords were generated due to a flawed random number generator, reducing password entropy significantly. This vulnerability could allow decryption of encrypted data with a dictionary attack.

Understanding CVE-2020-28924

Rclone, a cloud storage sync tool, was affected by a weak random number generator issue leading to the creation of easily guessable passwords.

What is CVE-2020-28924?

The vulnerability in Rclone versions prior to 1.53.3 resulted in the generation of weak passwords with reduced entropy, making decryption of encrypted data feasible through a dictionary attack.

The Impact of CVE-2020-28924

Weak passwords generated by affected versions could be decrypted with a plausible amount of effort.
Encryption of data using these weak passwords could be compromised.

Technical Details of CVE-2020-28924

Rclone's vulnerability stems from the flawed random number generator used in password generation.

Vulnerability Description

The weak random number generator in Rclone before version 1.53.3 led to the creation of easily guessable passwords, reducing password entropy significantly.

Affected Systems and Versions

Product: Rclone
Vendor: N/A
Versions affected: All versions before 1.53.3

Exploitation Mechanism

Passwords generated by affected versions depend deterministically on the time the second rclone was started, limiting password entropy.
Attackers could create a dictionary of possible passwords, making decryption of encrypted data feasible.

Mitigation and Prevention

Immediate Steps to Take:

Users of affected versions should change all passwords generated by the vulnerable Rclone versions.

Long-Term Security Practices:

Use strong, randomly generated passwords for encryption purposes.

Patching and Updates:

Update Rclone to version 1.53.3 or newer to mitigate the vulnerability.