CVE-2024-6563 in rcar_gen3_v2.5
Summary
by MITRE • 07/08/2024
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in Renesas arm-trusted-firmware allows Local Execution of Code. This vulnerability is associated with program files https://github.Com/renesas-rcar/arm-trusted-firmware/blob/rcar_gen3_v2.5/drivers/renesas/common/io/i... https://github.Com/renesas-rcar/arm-trusted-firmware/blob/rcar_gen3_v2.5/drivers/renesas/common/io/io_rcar.C .
In line 313 "addr_loaded_cnt" is checked not to be "CHECK_IMAGE_AREA_CNT" (5) or larger, this check does not halt the function. Immediately after (line 317) there will be an overflow in the buffer and the value of "dst" will be written to the area immediately after the buffer, which is "addr_loaded_cnt". This will allow an attacker to freely control the value of "addr_loaded_cnt" and thus control the destination of the write immediately after (line 318). The write in line 318 will then be fully controlled by said attacker, with whichever address and whichever value ("len") they desire.
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Analysis
by VulDB Data Team • 07/10/2024
The vulnerability identified as CVE-2024-6563 represents a classic buffer overflow flaw within the Renesas arm-trusted-firmware implementation, specifically affecting the R-Car Gen3 platform. This issue manifests in the io_rcar.c driver file where improper input validation leads to a dangerous condition that can be exploited for local code execution. The vulnerability stems from insufficient bounds checking on user-supplied data, creating a scenario where an attacker can manipulate memory layout and execution flow within the trusted firmware environment. Such flaws are particularly concerning in embedded systems and automotive applications where firmware integrity directly impacts system security and safety. The vulnerability has been classified under CWE-121 as a classic buffer overflow, which occurs when a program writes data beyond the boundaries of a fixed-length buffer, potentially overwriting adjacent memory locations.
The technical implementation of this vulnerability occurs at line 313 where the variable addr_loaded_cnt undergoes a validation check against CHECK_IMAGE_AREA_CNT (set to 5) but this check fails to prevent the subsequent buffer overflow condition. The flaw exists because the validation logic does not adequately protect against the overflow scenario that follows immediately at line 317, where buffer copying operations proceed without proper size verification. The function continues execution despite the initial bounds check, allowing the attacker to manipulate the addr_loaded_cnt variable through controlled input. This manipulation directly influences the memory destination of the subsequent write operation at line 318, where the attacker can specify arbitrary memory addresses and values for writing, effectively creating a controlled memory corruption scenario.
The operational impact of this vulnerability extends beyond simple code execution, as it enables an attacker with local access to potentially compromise the entire system security architecture. Within the context of automotive and embedded systems, this vulnerability could allow attackers to modify critical system parameters, bypass security checks, or even escalate privileges within the trusted execution environment. The attack vector requires local system access but the consequences are severe given that the affected firmware operates in a privileged security context. This vulnerability directly aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as attackers could leverage the buffer overflow to execute arbitrary code with elevated privileges. The severity is amplified because the vulnerable code operates within the ARM Trusted Firmware framework, which is responsible for maintaining secure boot processes and system-level security controls, making this a critical weakness in the security chain.
Mitigation strategies for CVE-2024-6563 should focus on implementing proper input validation and bounds checking mechanisms within the affected driver code. The primary fix involves strengthening the validation logic at line 313 to ensure that addr_loaded_cnt values are properly constrained before any buffer operations occur. Additionally, developers should implement defensive programming practices such as using safe string and memory copy functions that automatically perform bounds checking, and consider implementing stack canaries or other memory protection mechanisms. System administrators should ensure that affected firmware versions are updated promptly, as Renesas has released patches addressing this vulnerability. The solution also requires comprehensive code review processes to identify similar patterns within the broader codebase, particularly in other driver implementations that may exhibit similar buffer handling issues. Organizations should also implement runtime monitoring and intrusion detection systems to identify potential exploitation attempts, and consider adopting memory protection features such as address space layout randomization and data execution prevention to reduce the effectiveness of potential exploitation attempts.