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Amon2-6.01
⭐ Starred 163 / Amon2::Plugin::Web::CSRFDefender
Security Advisories (1)
CVE-2025-15604 (2026-03-28)

Amon2 versions before 6.17 for Perl use an insecure random_string implementation for security functions. In versions 6.06 through 6.16, the random_string function will attempt to read bytes from the /dev/urandom device, but if that is unavailable then it generates bytes by concatenating a SHA-1 hash seeded with the built-in rand() function, the PID, and the high resolution epoch time. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. Before version 6.06, there was no fallback when /dev/urandom was not available. Before version 6.04, the random_string function used the built-in rand() function to generate a mixed-case alphanumeric string. This function may be used for generating session ids, generating secrets for signing or encrypting cookie session data and generating tokens used for Cross Site Request Forgery (CSRF) protection.

NAME

Amon2::Plugin::Web::CSRFDefender - Anti CSRF filter

SYNOPSIS

package MyApp::Web;
use Amon2::Web;

__PACKAGE__->load_plugin('Web::CSRFDefender');

DESCRIPTION

This plugin denies CSRF request.

Do not use this with HTTP::Session2. Because HTTP::Session2 has XSRF token management function by itself.

WARNINGS

This module will split from Amon2 core distribution. You need to list this module in your cpanfile.

METHODS

$c->get_csrf_defender_token()

Get a CSRF defender token. This method is useful to add token for AJAX request.

$c->validate_csrf()

You can validate CSRF token manually.

PARAMETERS

no_validate_hook

Do not run validation automatically.

no_html_filter

Disable HTML rewriting filter. By default, CSRFDefender inserts XSRF token for each form element.

It's very useful but it hits performance issue if your site is very high traffic.

AUTHOR

Tokuhiro Matsuno

SEE ALSO

Amon2