Executive Summary
In 2024, security researchers uncovered a critical hardware and firmware vulnerability (CVE-2024-39432, CVE-2024-39431) affecting Unisoc UIS7862A modems widely used in modern vehicle head units. Attackers exploited a stack-based buffer overflow in the 3G RLC protocol to achieve unauthenticated remote code execution on the modem, bypassing standard mobile network security. Through this initial access, researchers leveraged hardware vulnerabilities to pivot laterally within the SoC, ultimately gaining privileged control over the Android Application Processor and demonstrating full system compromise—including running arbitrary code on the vehicle's infotainment system. This exposure places vehicle safety, user data privacy, and potentially road safety at significant risk.
The incident highlights the urgent and real-world impact of modem and embedded system vulnerabilities as vehicles become increasingly connected. With the proliferation of IoT in critical and mobile environments, attackers are targeting lower-level protocols and hardware integration points, complicating detection and remediation while amplifying the severity of breaches.
Why This Matters Now
This breach spotlights how embedded system vulnerabilities in automotive and IoT devices can facilitate deep, persistent compromises beyond software. As connected vehicles become mainstream, threats exploiting low-level modem or protocol flaws pose urgent risks to personal safety, data integrity, and regulatory compliance. Immediate action is critical for manufacturers and fleet operators.
Attack Path Analysis
Attackers initiated the compromise by remotely exploiting a critical stack-based buffer overflow (CVE-2024-39432) in the 3G RLC protocol on the vehicle's head unit modem, gaining code execution before security mechanisms were activated. They escalated privileges by crafting ROP chains and taking advantage of hardware-level flaws to modify execution permissions and persist payloads. The attackers moved laterally from the modem to the application processor (AP) by leveraging a hidden peripheral DMA device, ultimately patching the Android kernel. Using this foothold, they established two-way command and control over the head unit’s AP through NAS protocol manipulation. Sensitive system and potentially user data could then have been accessed or exfiltrated through established outbound channels. Ultimately, full control over the head unit enabled high impact such as remote arbitrary code execution—demonstrated by running unauthorized applications (e.g., Doom) on the infotainment system, with potential safety and privacy consequences.
Kill Chain Progression
Initial Compromise
Description
Attackers remotely exploited an RCE vulnerability in the 3G protocol stack (RLC), sending a specially crafted SDU packet to gain code execution on the modem before encryption or security controls were established.
Related CVEs
CVE-2024-39432
CVSS 8.3An out-of-bounds read in the UMTS RLC driver due to a missing bounds check could lead to remote denial of service.
Affected Products:
Unisoc UIS7862A – All versions prior to patch
Exploit Status:
proof of conceptCVE-2024-39431
CVSS 8.3An out-of-bounds write in the UMTS RLC driver due to a missing bounds check could lead to remote denial of service.
Affected Products:
Unisoc UIS7862A – All versions prior to patch
Exploit Status:
proof of concept
MITRE ATT&CK® Techniques
MITRE ATT&CK techniques mapped for quick filtering and SEO; additional enrichment possible with full STIX/TAXII pipeline.
User Execution
Endpoint Denial of Service
Exploitation for Privilege Escalation
System Services: Service Execution
Boot or Logon Autostart Execution: Shortcut Modification
Exploitation for Defense Evasion
Adversary-in-the-Middle: ARP Cache Poisoning
Exploitation of Remote Services
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Security of system components and software
Control ID: 6.2.1
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
DORA (Digital Operational Resilience Act) – ICT Risk Management
Control ID: Art. 9
CISA Zero Trust Maturity Model 2.0 – Visibility and Inventory of Assets
Control ID: Identity – Asset and Application Discovery
NIS2 Directive – Technical and Organizational Measures
Control ID: Art. 21(2)
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Automotive
Critical hardware/firmware vulnerabilities in vehicle head units enable remote code execution, compromising road safety and user data through cellular modem exploits.
Telecommunications
3G/4G/5G modem vulnerabilities expose cellular infrastructure to RLC protocol exploits, enabling bypassing of communication security mechanisms and network compromise.
Transportation
Connected vehicle systems face severe risks from modem-based attacks allowing remote control of critical transportation infrastructure and passenger safety systems.
Computer Hardware
System-on-Chip vulnerabilities in Unisoc processors demonstrate hardware-level security flaws affecting integrated communication processors across multiple device categories.
Sources
- God Mode On: how we attacked a vehicle’s head unit modemhttps://securelist.com/attacking-car-modem/118463/Verified
- Kaspersky identified security flaws in Unisoc system-on-chip, enabling remote hijackinghttps://me-en.kaspersky.com/about/press-releases/kaspersky-identified-security-flaws-in-unisoc-system-on-chip-enabling-remote-hijackingVerified
- Android Security Bulletin—September 2024https://source.android.com/docs/security/bulletin/2024-09-01Verified
- CVE-2024-39432 : In UMTS RLC driver, there is a possible out of bounds read due to a missing bounds checkhttps://www.cvedetails.com/cve/CVE-2024-39432/Verified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Applying Zero Trust segmentations, real-time inline threat detection, encrypted east-west and egress traffic controls, and centralized policy enforcement could have significantly limited the attackers' ability to compromise, pivot within, and control vulnerable networked vehicle systems. Explicit network segmentation and enforced policy boundaries would detect or block unauthorized lateral movement, malicious inbound packets, and anomalous control messages early in the attack.
Control: Encrypted Traffic (HPE)
Mitigation: Encrypted and authenticated network channels impede unauthorized packet injection or exploit delivery.
Control: Threat Detection & Anomaly Response
Mitigation: Anomalous process or firmware-level changes are detected and alerted in real-time.
Control: East-West Traffic Security
Mitigation: Unauthorized workload-to-workload or service-to-service traffic is inspected and restricted.
Control: Threat Detection & Anomaly Response
Mitigation: C2 traffic abnormalities or unexpected NAS protocol exchanges are detected and can be blocked or flagged for incident response.
Control: Egress Security & Policy Enforcement
Mitigation: Unauthorized outbound connections or suspicious data flows are blocked or logged.
Compromised components are isolated; blast radius of any breach is minimized.
Impact at a Glance
Affected Business Functions
- Vehicle Infotainment Systems
- Telematics Services
Estimated downtime: 7 days
Estimated loss: $500,000
Potential exposure of user data including navigation history, personal contacts, and vehicle telemetry.
Recommended Actions
Key Takeaways & Next Steps
- • Implement encrypted and authenticated traffic for all vehicle telematics communication channels (e.g., MACsec, IPsec) to prevent exploit delivery.
- • Enforce robust east-west segmentation and visibility between all system-on-chip (SoC) components and networked workloads to contain lateral movement.
- • Deploy comprehensive threat detection and anomaly response for real-time monitoring of process behavior and protocol-level communications.
- • Apply strict egress policy enforcement to restrict outbound connections and prevent potential data exfiltration from head units or vehicle systems.
- • Adopt zero trust segmentation and least-privilege access across connected vehicle ecosystem components, minimizing attack surface and limiting blast radius in the event of compromise.
