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The vulnerability exists within the modem firmware’s Radio Resource Control (RRC) protocol stack. When a User Equipment (UE), such as a smartphone, connects to a cellular network, it exchanges RRC signaling messages with the base station. The flaw is a lack of proper bounds and structure validation for specific information elements within these messages. A physically proximate attacker can set up a malicious, software-defined radio (SDR) base station broadcasting a legitimate-seeming cell identity. When a vulnerable UE performs initial attachment or handover to this rogue base station, the attacker transmits a specially crafted RRC packet containing a malformed, non-compliant information element. The modem’s parsing logic fails to validate this input, leading to an out-of-bounds read or a null pointer dereference when the firmware attempts to process the element. This triggers a fatal exception within the modem’s real-time operating system (RTOS), resulting in a full modem subsystem crash and reboot. This causes a sustained denial of service, dropping all cellular connectivity (voice, data, SMS) until the modem resets and re-attempts network search, which could be forced to reconnect to the malicious cell again.
Platform: MediaTek Modem
Version: Multiple
Vulnerability: Improper Input Validation
Severity: Critical
date: 12/01/2025
Prediction: Q1 2025
What Undercode Say:
Check current modem firmware version adb shell getprop gsm.version.baseband Monitor kernel for modem crash events (QMI/AT interface errors) dmesg | grep -i "modem|ssr|subsys" Raw AT command to query modem status (may vary) adb shell atcmd AT+EGMR=0,7
How Exploit:
- Attacker sets up rogue base station (e.g., OpenAirInterface, srsRAN).
- Broadcasts attractive cell ID to lure target UEs.
3. Waits for UE RRC Connection Request.
- Responds with malicious RRC Connection Setup containing invalid IE.
5. Victim modem crashes parsing malicious payload.
Protection from this CVE:
Apply vendor patch (MOLY01673751). Disable automatic network selection, use manual operator selection. Monitor for unexplained signal loss.
Impact:
Remote Denial of Service, sustained loss of all cellular connectivity, potential battery drain from repeated crash/reboot cycles.
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Sources:
Reported By: nvd.nist.gov
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