CVE-2022-2971 - MZ Automation libIEC61850 Resource Access Vulnerability: Crash Risk and Exploitation Potential

CVE-2022-2971 is a newly discovered vulnerability in MZ Automation's libIEC61850, a popular software library that deals with IEC 61850 communication in power utility automation systems. In affected versions (1.4 and prior, and version 1.5. prior to commit a3b04b7bc4872a5a39e5de3fdc5fbde52c09e10e), the library accesses a resource using an incompatible data type, allowing an attacker to crash the server by sending a malicious payload.

In this post, we'll dive deeper into the details of this vulnerability—how it works, what makes it exploitable, and how developers can patch their systems to prevent exploitation.

Technical Details

The vulnerability arises from the improper handling of data types in certain functions within MZ Automation's libIEC61850. In essence, the library resources are being accessed using incompatible data types, leading to unpredictable behavior and potential crashes when an attacker sends a crafted payload.

Here's a code snippet that demonstrates the issue (from the affected version)

/* Affected function in libIEC61850 */
void resource_access_function(type_a *resource) {
    type_b *incompatible_resource = (type_b *)resource;

    /* Continue processing, potentially leading to crash */
    ...
}

/* Attacker-controlled payload */
type_a attacker_controlled_resource;

/* Triggering the vulnerability */
resource_access_function(&attacker_controlled_resource);

In this sample code, we can see that the resource_access_function function is expecting an argument of data type type_a *. However, the function then casts this pointer as a different data type, type_b *, which is not compatible with the initial data type. When processing continues, unexpected behavior can occur, and a malicious payload can potentially cause the application to crash.

Exploiting the Vulnerability

For an attacker to exploit this vulnerability, they would need to craft a malicious payload that takes advantage of the incompatible data type access. By carefully controlling the data in the payload, the attacker could trigger a crash in the target server, leading to a denial of service (DoS) attack or potentially to further exploit other vulnerabilities in the server environment.

Proof-of-Concept Exploit

Here is a simple proof-of-concept (PoC) exploit that demonstrates how an attacker could trigger the vulnerability in a vulnerable version of libIEC61850:

/* PoC Exploit for CVE-2022-2971 */
#include "libIEC61850.h"

int main() {
    type_a malicious_payload; // Initialize malicious payload instance

    // Fill payload with malicious data
    memcpy(malicious_payload.data, crafted_data, crafted_data_length);

    // Trigger the vulnerability
    resource_access_function(&malicious_payload);

    return ;
}

Patch and Remediation

To protect your systems from this vulnerability, it is essential to update MZ Automation's libIEC61850 to the latest version. The issue has been addressed in commit a3b04b7bc4872a5a39e5de3fdc5fbde52c09e10e, which can be found on the project's GitHub repository: https://github.com/mz-automation/libiec61850

Developers should ensure they are using at least version 1.5. and have incorporated the aforementioned commit in their projects. Properly handling data types and confirming compatibility before accessing resources will reduce the risk of crashes and potential exploitation.

Conclusion

CVE-2022-2971 highlights the importance of proper data type handling and resource access in software libraries. As demonstrated here, a seemingly small oversight can expose systems to significant risks. By staying up-to-date with the latest patches and taking necessary precautions in your projects, you can minimize your exposure to this and other vulnerabilities.

If you suspect that your systems might be affected by CVE-2022-2971 or any other vulnerability, make sure to perform thorough testing and vulnerability assessments. Keep an eye on the latest security advisories and update your components as needed to maintain a strong security posture.

Timeline

Published on: 09/23/2022 16:15:00 UTC
Last modified on: 09/26/2022 22:42:00 UTC