CVE-2025-54351 in iperf3
Summary
by MITRE • 08/03/2025
In iperf before 3.19.1, net.c has a buffer overflow when --skip-rx-copy is used (for MSG_TRUNC in recv).
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Analysis
by VulDB Data Team • 08/05/2025
The vulnerability identified as CVE-2025-54351 affects the iperf network performance testing tool version 3.19.1 and earlier, specifically within the net.c source file. This buffer overflow occurs when the --skip-rx-copy command-line option is utilized, which is designed to optimize network receive operations by skipping certain data copying mechanisms. The flaw manifests during the handling of MSG_TRUNC flag in recv system calls, which indicates that the received data may have been truncated due to buffer limitations. This particular configuration creates a scenario where the application fails to properly validate buffer boundaries when processing incoming network data, leading to potential memory corruption.
The technical implementation of this vulnerability stems from improper bounds checking in the network receive path of iperf's networking code. When --skip-rx-copy is enabled, the software bypasses standard data copying procedures and directly processes received packets, assuming that the underlying socket buffer will provide adequate space for data reception. However, the MSG_TRUNC flag indicates that the kernel has truncated the received data because it exceeded the allocated buffer size. The code in net.c does not account for this truncation scenario properly, leading to a situation where data is written beyond the allocated buffer boundaries. This represents a classic buffer overflow condition classified as CWE-121, which occurs when insufficient space is allocated for data, or CWE-787, which involves writing beyond the boundaries of a fixed-length buffer. The vulnerability specifically impacts the receive path of network operations and can be exploited through carefully crafted network traffic that triggers the MSG_TRUNC condition.
The operational impact of this vulnerability extends beyond simple memory corruption, as it presents significant security risks to systems running vulnerable versions of iperf. Network administrators who use iperf for performance testing and monitoring may inadvertently expose their systems to remote code execution or denial of service attacks. The buffer overflow can be triggered by malicious network traffic that causes the kernel to return data with the MSG_TRUNC flag set, allowing attackers to potentially overwrite adjacent memory locations and execute arbitrary code with the privileges of the iperf process. The vulnerability is particularly concerning in environments where iperf is used in server configurations or when the tool is run with elevated privileges, as it could be exploited to compromise the entire system. Additionally, the nature of network performance testing tools makes them attractive targets for attackers seeking to establish persistent access or to disrupt network operations through resource exhaustion attacks.
Mitigation strategies for CVE-2025-54351 should focus on immediate version upgrades to iperf 3.19.1 or later, which contain the necessary patches to address the buffer overflow condition. System administrators should also consider implementing network segmentation and access controls to limit exposure of iperf instances to untrusted networks. The use of the --skip-rx-copy flag should be carefully evaluated and potentially disabled in production environments where security is a primary concern. Network monitoring solutions should be configured to detect unusual patterns in iperf usage that might indicate exploitation attempts, particularly around network traffic that triggers MSG_TRUNC conditions. Organizations should also consider implementing additional runtime protections such as address space layout randomization and stack canaries to mitigate potential exploitation. From an ATT&CK perspective, this vulnerability maps to T1059.007 for remote code execution and T1499.004 for network disruption, making it a critical concern for defensive security teams. The vulnerability demonstrates the importance of proper input validation and buffer management in network applications, particularly those that handle user-provided or network-generated data without adequate bounds checking.