Headline
CVE-2023-27100: Bug #13574: Extra remote address information can confuse ``sshguard`` - pfSense
Improper restriction of excessive authentication attempts in the SSHGuard component of Netgate pfSense Plus software v22.05.1 and pfSense CE software v2.6.0 allows attackers to bypass brute force protection mechanisms via crafted web requests.
closed
Extra remote address information can confuse ``sshguard``
Plus Target Version:
23.01
Description
The authentication system attempts to be informative and print extra information along with IP addresses to completely identify where a user logs in from. This includes the authentication source (e.g. local database, LDAP or RADIUS, auth server name), contents of proxy headers such as X-Forwarded-For or Client-IP to further clarify exactly where a user is located.
This extra information is printed after the IP address of the remote user in various places, including log messages for authentication.
The extra information confuses the sshguard parser and it fails to recognize the client IP address in authentication error messages, so the protection may not be enforced depending on the content of the request headers.
While this extra information can be helpful, it isn’t relevant for authentication failures since (a) the auth source is unknown/undefined as it failed every attempt and (b) since the login failed the rest of the headers shouldn’t be trusted anyhow. Thus, we can safely remove it from the error messages.
History
Notes
Property changes
Associated revisions
Status changed from In Progress to Feedback
% Done changed from 0 to 100
Status changed from Feedback to Resolved
The extra information is no longer printed in the log, and sshguard properly recognizes the failed attempts even when the client provides the X-Forwarded-For or Client-IP headers.
- Private changed from Yes to No
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pfsenseCE version 2.6.0 suffers from an anti-brute force protection bypass vulnerability.