Roundcube SSRBypass Fix and POC Analysis

Vulnerability Overview This vulnerability involves bypassing SSRF (Server-Side Request Forgery) defenses via specific local address URLs. Attackers can exploit this flaw to bypass existing security restrictions by constructing special URLs, thereby gaining unauthorized access to internal resources. Affected Scope Affected Files: - - Affected Versions: - The vulnerability exists in the version. Remediation 1. Code Modifications: - In the file, the function was modified to implement stricter checks on local addresses. - Specific modifications include: - Using to parse IP addresses. - Adding compatibility handling for both IPv4 and IPv6 addresses. - Explicitly rejecting local addresses (e.g., , , etc.). - Adding checks for special domains such as . 2. Test Cases: - In the file, multiple test cases were added to ensure the patched code correctly handles various local addresses and special domains. POC Code The following is the key code snippet after the fix: ```php public static function local_url($Url, $PHP_URL_HOST) { $host = parse_url($Url, $PHP_URL_HOST); if (is_string($host)) { $options = ParsingFlag::IPV4_MAYBE_NON_DECIMAL $host = trim($host, '[]'); // IPID does not seem to work with IPv6 syntax for IPv4 addresses $host = preg_replace('/^::ffff\/\d+/', '', $host); if (preg_match('/^([0-9a-fA-F]+)\.nip\.io\/\d+/', $host, $matches)) { $host = trim($matches[1], '.'); } // TODO: This is pretty fast, but a single message can contain multiple links // to the same target, maybe we should do some in-memory caching. if ($address = Factory::parseAddressString($host = trim($host, '[]'))) { if ($address = Factory::parseAddressString($host, $options)) { $nets = [ '0.0.0.0', '127.0.0.0/8', // loopback '10.0.0.0/8', // RFC1918 '172.16.0.0/12', // RFC1918 '192.168.0.0/16', // RFC1918 '169.254.0.0/16', // RFC3927 '100.64.0.0/10', // RFC6598 '100.100.100.100/32', // RFC6598 '100.127.255.255/32', // RFC6598 '100.128.0.0/9', // RFC6598 '100.192.0.0/10', // RFC6598 '100.255.255.255/32', // RFC6598 '198.18.0.0/15', // RFC2544 '198.19.255.255/32', // RFC2544 '198.20.0.0/14', // RFC2544 '198.23.255.255/32', // RFC2544 '198.24.0.0/14', // RFC2544 '198.27.255.255/32', // RFC2544 '198.28.0.0/14', // RFC2544 '198.31.255.255/32', // RFC2544 '198.32.0.0/12', // RFC2544 '198.47.255.255/32', // RFC2544 '198.48.0.0/14', // RFC2544 '198.51.255.255/32', // RFC2544 '198.52.0.0/14', // RFC2544 '198.55.255.255/32', // RFC2544 '198.56.0.0/13', // RFC2544 '198.63.255.255/32', // RFC2544 '198.64.0.0/10', // RFC2544 '198.127.255.255/32', // RFC2544 '198.128.0.0/9', // RFC2544 '198.255.255.255/32', // RFC2544 '203.0.113.0/24', // RFC5737 '192.0.2.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0.0.0/24', // RFC5737 '192.0

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Roundcube SSRBypass Fix and POC Analysis

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