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How the CVE Works:
Yggdrasil, a system broker, facilitates inter-process communication via DBus. The vulnerability arises due to missing authentication checks in a DBus method responsible for dispatching messages to worker processes. A Yggdrasil worker with package management privileges (e.g., installing RPMs) can be exploited by any local user due to this oversight. Attackers craft malicious DBus calls, forcing the worker to install unauthorized packages, leading to privilege escalation. The lack of authorization validation allows unprivileged users to execute high-impact operations, compromising system integrity.
DailyCVE Form:
Platform: Yggdrasil
Version: <1.2.3
Vulnerability: Privilege Escalation
Severity: High
Date: May 14, 2025
What Undercode Say:
Exploitation:
1. Craft malicious DBus call to Yggdrasil worker:
dbus-send --system --dest=org.yggdrasil /org/yggdrasil org.yggdrasil.Worker.InstallPackage string:"malicious.rpm"
2. Use `gdbus` to exploit the unprotected method:
gdbus call --system -d org.yggdrasil -o /org/yggdrasil -m org.yggdrasil.Worker.Dispatch "malicious_payload"
Mitigation:
1. Patch Yggdrasil to enforce DBus method authentication:
// Example patch: Validate caller UID
if (dbus_message_get_sender(msg) != "root") {
dbus_respond_error(msg, "Access denied");
}
2. Restrict Yggdrasil worker capabilities:
systemctl edit yggdrasil-worker --drop-capability=CAP_CHOWN,CAP_DAC_OVERRIDE
3. Block unauthorized DBus traffic:
busctl policy --system org.yggdrasil "deny user="
Detection:
1. Audit DBus activity for suspicious calls:
journalctl -u dbus --grep "org.yggdrasil" | grep -v "root"
2. Check for unexpected RPM installations:
rpm -qa --last | head -n 10
References:
Sources:
Reported By: github.com
Extra Source Hub:
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