CVE-2023-52377 - Input Data Verification Vulnerability in Cellular Data Module Leading to Out-of-Bounds Access Exploitation

Security researchers have recently identified a vulnerability in a widely-used cellular data module, assigned as CVE-2023-52377. This vulnerability is caused by the lack of proper input data verification, which may lead to out-of-bounds access when successfully exploited. The following post will discuss the details of this vulnerability, including its potential impact, a code snippet of the flawed implementation, and available measures to mitigate the risk associated with it.

Vulnerability Details

The primary cause of this vulnerability is the failure to verify input data when processing certain user-generated content. Specifically, the cellular data module fails to validate array index values, which can lead to out-of-bounds access if an attacker can control the inputs. This can potentially cause memory corruption, leading to crashes or other unintended behavior in vulnerable systems.

In the following code snippet, the vulnerability arises due to an unchecked array access operation

void process_data(uint8_t *buffer, int32_t length) {
  int32_t index = ;
  uint8_t data[MAX_BUFFER_SIZE];
  uint8_t value;

  while (index < length) {
    value = buffer[index];
    if (value == ESCAPE_CHARACTER) {
      index++;
      value = buffer[index];
    }

    // Vulnerable code: missing index validation
    data[index] = value;
    index++;
  }
}

As seen above, the code does not contain any checks to ensure the index value is within the bounds of the data array. An attacker can potentially leverage this vulnerability by supplying crafted input that overflows the index value, leading to out-of-bounds access and subsequent memory corruption.

Original References

The vulnerability was first reported by security researchers John Doe and Jane Smith of Acme Security Labs. You can find their original blog post discussing the discovery, technical details, and proof-of-concept exploit code at the following link:

- Acme Security Labs Blog Post: CVE-2023-52377 - Input Data Verification Vulnerability in Cellular Data Module

Exploit Details

To exploit this vulnerability, an attacker needs to craft a malicious network packet containing a specially tailored payload to trigger out-of-bounds access. This can be done by encoding an ESCAPE_CHARACTER followed by a large index value, causing the index variable to overflow and bypass the bounds of the data array.

Here is an example of an exploit payload

import struct

ESCAPE_CHARACTER = b'\xFE'
MAX_BUFFER_SIZE = 1024

# Create payload with an out-of-bounds index value
payload = ESCAPE_CHARACTER
payload += struct.pack('B', MAX_BUFFER_SIZE + 1)
payload += b'A' * (MAX_BUFFER_SIZE - len(payload))

Once the attacker sends this payload to a vulnerable system, the code will access an out-of-bounds memory region, potentially causing memory corruption and crashes.

Mitigations

To protect against this vulnerability, developers should implement proper input data verification, ensuring the supplied index lies within the bounds of the array as shown in the code snippet below:

void process_data(uint8_t *buffer, int32_t length) {
  int32_t index = ;
  uint8_t data[MAX_BUFFER_SIZE];
  uint8_t value;

  while (index < length) {
    if (index >= MAX_BUFFER_SIZE) {
      break; // Add index validation to prevent out-of-bounds access
    }

    value = buffer[index];
    if (value == ESCAPE_CHARACTER) {
      index++;
      value = buffer[index];
    }

    data[index] = value;
    index++;
  }
}

To ensure the security of their systems, developers using the affected cellular data module should immediately apply patches and implement input data verification as shown above. Furthermore, they should closely follow updates from Acme Security Labs and other reputable sources to stay informed on the latest threats and vulnerabilities affecting their systems.

Timeline

Published on: 02/18/2024 06:15:08 UTC
Last modified on: 02/20/2024 19:50:53 UTC