Weak Password RNG in Nextcloud Server Shares (before 24.0.10)
CVE-2023-28835 Published on March 30, 2023
Insecure randomness for default password in nextcloud
Nextcloud server is an open source home cloud implementation. In affected versions the generated fallback password when creating a share was using a weak complexity random number generator, so when the sharer did not change it the password could be guessable to an attacker willing to brute force it. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. This issue only affects users who do not have a password policy enabled, so enabling a password policy is an effective mitigation for users unable to upgrade.
Vulnerability Analysis
CVE-2023-28835 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
What is a PRNG Vulnerability?
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
CVE-2023-28835 has been classified to as a PRNG vulnerability or weakness.
Products Associated with CVE-2023-28835
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Affected Versions
nextcloud security-advisories:- Version < 24.0.10 is affected.
- Version >= 25.0.0, < 25.0.4 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.