CVE-2024-7543 in oFono
Summary
by MITRE • 08/06/2024
oFono SimToolKit Heap-based Buffer Overflow Privilege Escalation Vulnerability. This vulnerability allows local attackers to execute arbitrary code on affected installations of oFono. An attacker must first obtain the ability to execute code on the target modem in order to exploit this vulnerability.
The specific flaw exists within the parsing of STK command PDUs. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-23456.
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Analysis
by VulDB Data Team • 04/17/2026
The CVE-2024-7543 vulnerability represents a critical heap-based buffer overflow in the oFono SimToolKit implementation that exposes systems to privilege escalation attacks. This vulnerability resides within the modem communication stack of the oFono telephony stack, which serves as a core component in Linux-based mobile device systems and embedded telecommunications equipment. The flaw specifically manifests during the parsing of SimToolKit command protocol data units, where insufficient input validation allows malicious data to overwrite adjacent heap memory regions. This vulnerability type maps directly to CWE-121 Heap-based Buffer Overflow, a well-documented weakness that has historically enabled attackers to achieve arbitrary code execution through memory corruption exploits. The vulnerability requires local attacker access to the target modem environment, making it particularly concerning for systems where modem access is not properly restricted.
The technical exploitation of this vulnerability occurs through the improper handling of SimToolKit command PDUs, which are standardized protocols used by mobile networks to deliver interactive services to SIM cards. When oFono processes these PDUs, it fails to validate the length of incoming data before performing memory copy operations into heap-allocated buffers. This validation gap allows attackers to craft malicious PDUs that exceed the allocated buffer size, causing a heap overflow condition that can overwrite critical memory structures including function pointers, return addresses, or other control data. The exploitation chain requires an attacker to first gain code execution capability on the target modem, which typically involves compromising the modem's communication interface or exploiting a separate vulnerability in the modem firmware. The attack leverages the fact that oFono operates with elevated privileges in modem contexts, making successful exploitation result in code execution within the service account context.
The operational impact of CVE-2024-7543 extends beyond simple privilege escalation, as it can enable attackers to gain persistent access to critical telecommunications infrastructure. This vulnerability affects systems where oFono is deployed as the primary telephony management stack, including embedded devices, mobile base stations, and network infrastructure equipment that relies on SIM card interaction for service provisioning. The attack vector is particularly concerning because modem interfaces are often less restricted than other system components, potentially allowing attackers to establish footholds through network-based attacks or physical access. The vulnerability's exploitation can lead to complete system compromise, enabling attackers to intercept communications, modify network configurations, or establish backdoors for continued access. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation allows attackers to execute arbitrary code within the target environment with elevated privileges. The vulnerability also maps to ATT&CK technique T1068 for Exploitation for Privilege Escalation, as the heap overflow directly enables privilege escalation within the service context.
Mitigation strategies for CVE-2024-7543 require a multi-layered approach addressing both immediate remediation and long-term architectural improvements. The primary recommendation involves applying patches from the upstream oFono project that implement proper input validation for SimToolKit command PDUs, ensuring that all user-supplied data is strictly validated against buffer boundaries before memory operations occur. System administrators should implement strict access controls around modem interfaces, limiting physical and network access to these critical components to prevent unauthorized code execution. Network segmentation and firewall rules should be enforced to restrict communication with modem interfaces to authorized management systems only. Additionally, implementing runtime protections such as heap canaries, stack canaries, and address space layout randomization can provide defense-in-depth against exploitation attempts. Monitoring solutions should be deployed to detect anomalous SimToolKit command processing patterns that could indicate exploitation attempts. The vulnerability highlights the importance of secure coding practices and input validation, particularly for protocols handling user-supplied data in telecommunications infrastructure, aligning with industry standards that emphasize the need for robust buffer overflow protections in system components handling external input. Organizations should also conduct thorough security assessments of their modem interfaces and related telephony stacks to identify similar vulnerabilities that may exist in other components of their telecommunications infrastructure.