PHP, Denial of Service (DoS), CVE-2023-XXXX (Low)

How the Mentioned CVE Works:

The vulnerability arises from the improper use of the `explode()` function in PHP, which lacks a default limit parameter. This allows malicious clients to send specially crafted packets that cause excessive CPU and memory usage on the server. The issue is particularly exploitable in scenarios involving packet processing, such as sign editing, JWT parsing in LoginPacket, and command parsing. While the impact is mitigated by other constraints like packet decompression limits, the vulnerability can still lead to resource exhaustion attacks. The fix, introduced in version 5.25.2, enforces the use of the `limit` parameter in all `explode()` calls, preventing such abuse.

DailyCVE Form:

Platform: PHP
Version: <5.25.2
Vulnerability: DoS via `explode()`
Severity: Low
Date: 2023-XX-XX

What Undercode Say:

Exploitation:

Craft Malicious Packets: Send packets with excessive delimiters to trigger uncontrolled `explode()` calls.
Target Specific Functions: Focus on functions like sign editing or JWT parsing that use `explode()` without limits.
Resource Exhaustion: Repeatedly send such packets to exhaust server CPU and memory.

Protection:

Update PHP: Upgrade to version 5.25.2 or later.
Enforce Limits: Ensure all `explode()` calls include the `limit` parameter.
Input Validation: Pre-process incoming data to limit the number of delimiters.

Commands:

Check PHP Version:
```
php -v
```

Update PHP:

sudo apt-get update && sudo apt-get upgrade php

Code Snippets:

Vulnerable Code:
```
$parts = explode("\n", $input);
```

Fixed Code:

$parts = explode("\n", $input, 4); // Limit to 4 parts

Analytics:

Impact: Low due to existing packet decompression limits.
Exploit Complexity: Moderate, requiring crafted packets.
Mitigation Difficulty: Easy, via updates and code fixes.

References:

bash
bash
By following these steps, users can mitigate the risk of this vulnerability and ensure their systems remain secure.

References:

Reported By: https://github.com/advisories/GHSA-g274-c6jj-h78p
Extra Source Hub:
Undercode

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram