Username enumeration via distinct login responses
Published Oct 4, 2021 · Updated Aug 4, 2024
Username enumeration in Xiuno BBS 4.0.4 allows remote attackers to identify registered usernames via distinct login responses. In route/user.php, the POST login handler passes a non-email email parameter to user_read_by_username() and returns an account-specific error when no matching user exists. No authentication is required; repeated crafted login requests disclose registered usernames without exposing passwords or modifying data.
Summary
What happened
Username enumeration in Xiuno BBS 4.0.4 allows remote attackers to identify registered usernames via distinct login responses. In route/user.php, the POST login handler passes a non-email email parameter to user_read_by_username() and returns an account-specific error when no matching user exists. No authentication is required; repeated crafted login requests disclose registered usernames without exposing passwords or modifying data.
The record
- CVE
- CVE-2020-21493
- Published
- Oct 4, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1087
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 4, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- User Name Enumeration Vulnerability proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo