Glib: path traversal in glib/gio/gdbusauthmechanismsha1.c via keyring_lookup_entry and mechanism_client_data_receive
A flaw was found in GLib. The D-Bus client-side implementation of the DBUS_COOKIE_SHA1 SASL authentication mechanism does not validate the cookie_context parameter received from the server. A malicious D-Bus server can supply a cookie_context containing path traversal sequences, causing the client to read an arbitrary file and exfiltrate sensitive data by verifying guessed file contents against a generated hash.
To mitigate this vulnerability, ensure that applications only connect to trusted D-Bus servers and operate within secure, isolated networks to prevent man-in-the-middle (MitM) attacks. If feasible, configuring the D-Bus connection to strictly require the EXTERNAL authentication mechanism and disabling DBUS_COOKIE_SHA1 will completely neutralize this issue.
Exploits
Credits
Red Hat would like to thank Thepwnisher for reporting this issue.