CVE-2025-40596: Stack-Based Buffer Overflow in SonicWall SMA100 Series Web Interface
A critical vulnerability has been discovered in the web interface of the SonicWall SMA100 series. This flaw allows an unauthenticated, remote attacker to potentially cause a Denial of Service (DoS) condition, or even achieve arbitrary code execution. Let's dive into the details and understand the risks.
Vulnerability Details
- CVE ID: CVE-2025-40596
- Description: A stack-based buffer overflow vulnerability exists in the SMA100 series web interface. This allows an unauthenticated attacker to cause a Denial of Service (DoS) or potentially execute code remotely.
- CVSS Score: 7.3 HIGH
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- CVSS Explanation: This means an attacker can exploit the vulnerability remotely over the network with low complexity and without any required privileges or user interaction. The impact includes limited confidentiality, integrity, and availability. Essentially, an attacker can read some sensitive information, modify some data, and disrupt services to some extent.
- Exploit Requirements: An attacker only needs network access to the vulnerable SMA100 web interface. No authentication is required.
- Affected Vendor: SonicWall
- Affected Product: SMA100 Series
- Affected Version: Versions prior to patched releases. (Check SonicWall's advisory for specific versions)
- CWE: CWE-121 - Stack-based Buffer Overflow. This occurs when a program writes beyond the allocated buffer on the stack, potentially overwriting adjacent data or control flow information, leading to crashes or arbitrary code execution.
Timeline of Events
- 2025-07-23: CVE ID assigned and vulnerability disclosed to SonicWall.
- 2025-07-23: Initial vulnerability report published.
- [Future Date]: Patch released by SonicWall (Check SonicWall's PSIRT for updates).
Exploitability & Real-World Risk
This vulnerability is highly exploitable because it requires no authentication and has a low attack complexity. An attacker could potentially craft a malicious request to the SMA100 web interface, overflowing the buffer and causing a denial of service. More sophisticated attackers could potentially use this flaw to execute arbitrary code on the appliance, gaining complete control. Given the role of SMA100 in providing secure remote access, a successful exploit could compromise entire networks.
Recommendations
- Apply Patches: Immediately apply the latest security patches released by SonicWall for the SMA100 series.
- Network Segmentation: Implement network segmentation to limit the blast radius in case of a successful exploit.
- Monitor Logs: Monitor logs for suspicious activity related to the SMA100 web interface.
- Disable Unused Features: Disable any unnecessary features on the SMA100 appliance to reduce the attack surface.
- Web Application Firewall (WAF): Consider deploying a WAF in front of the SMA100 to detect and block malicious requests.
Technical Insight
A stack-based buffer overflow typically arises when a program copies more data into a fixed-size buffer located on the stack than it can hold. In this case, the SMA100 web interface likely has a component that handles user input without proper bounds checking. An attacker can exploit this by sending a specially crafted input that exceeds the buffer's capacity, overwriting adjacent memory on the stack. This can lead to a crash (DoS) or, with careful crafting, allow the attacker to hijack control flow and execute arbitrary code.
Credit to Researcher(s)
SonicWall PSIRT
References
Tags
#CVE-2025-40596 #SonicWall #SMA100 #BufferOverflow #RCE #DoS #Vulnerability #Security
Summary: A stack-based buffer overflow vulnerability in the SonicWall SMA100 series web interface allows remote, unauthenticated attackers to potentially cause a Denial of Service (DoS) or execute arbitrary code. Patch immediately.
CVE ID: CVE-2025-40596
Risk Analysis: Successful exploitation could lead to denial of service, data theft, or complete system compromise, potentially impacting entire networks that rely on the SMA100 for remote access.
Recommendation: Apply the latest security patches released by SonicWall. Implement network segmentation and monitor logs for suspicious activity.
Timeline
- 2025-07-23: CVE ID assigned and vulnerability disclosed.
- 2025-07-23: Initial vulnerability report published.