Vulnerabilities > CVE-2021-32653 - Information Exposure Through Sent Data vulnerability in Nextcloud Server
Attack vector
NETWORK Attack complexity
LOW Privileges required
HIGH Confidentiality impact
LOW Integrity impact
NONE Availability impact
NONE Summary
Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server versions prior to 19.0.11, 20.0.10, or 21.0.2 send user IDs to the lookup server even if the user has no fields set to published. The vulnerability is patched in versions 19.0.11, 20.0.10, and 21.0.2; no workarounds outside the updates are known to exist.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Choosing a Message/Channel Identifier on a Public/Multicast Channel Attackers aware that more data is being fed into a multicast or public information distribution means can 'select' information bound only for another client, even if the distribution means itself forces users to authenticate in order to connect initially. Doing so allows the attacker to gain access to possibly privileged information, possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could change its identifier from a less privileged to more so privileged channel or command.
- Exploiting Incorrectly Configured SSL Security Levels An attacker may take advantage of a setting in SSL that allows for weaknesses within that setting to be exploited to gain access to data intended to be encrypted, or injection commands or other traffic into the encrypted stream to cause compromise of either the client or server.