CVE-2022-35881: Exploring Format String Injection Vulnerabilities in Abode Systems iota All-In-One Security Kit

In this long-read, we will delve deep into the details of CVE-2022-35881, a security vulnerability that affects the iota All-In-One Security Kit developed by Abode Systems, Inc. The affected software versions are 6.9Z and 6.9X. The vulnerability pertains to four format string injection weaknesses that exist within the Universal Plug and Play (UPnP) logging functionality. Exploiting these vulnerabilities could potentially lead to memory corruption, information disclosure, and denial of service.

An attacker can trigger these vulnerabilities by hosting a malicious UPnP service. Let's explore the technicalities of the vulnerability, including the faulty code snippet and methods to identify and exploit these weaknesses.

Vulnerability Details

CVE-2022-35881 originates due to format string injection through errorCode and errorDescription XML tags. The DoUpdateUPnPbyService action handler makes use of these specific tags. The vulnerability is a direct consequence of insufficient sanitization of input received via UPnP requests. The code snippet below shows the affected code in DoUpdateUPnPbyService handler:

static void DoUpdateUPnPbyService(struct upnphttp * h, const char * action)
{
    ...        
    if(error)
    {
        syslog(LOG_NOTICE, "UPnP/%s error: %s, %s", action, ErrorCode, ErrorDescription);
        BuildErrorResponse(h, ErrorCode, ErrorDescription);
    }
    else
    {
        BuildSendAndCloseSoapResp(h, body, strlen(body));
    }
    ...
}

Here, syslog is called using the unsanitized ErrorCode and ErrorDescription coming from the UPnP request. This introduces four format string injection vulnerabilities in the logging functionality. For reference, consult the source code on GitHub: Abode Systems iota All-In-One Security Kit

Exploitation

An attacker can trigger the vulnerabilities by hosting a malicious UPnP service on the same network as the target device. By sending a specially crafted UPnP negotiation message containing format string specifiers such as %x or %n, the attacker can cause memory corruption, disclose sensitive information, or crash the software. Here's an example of a malformed UPnP request:

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"; s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">;
  <s:Body>
    <u:DoUpdateUPnPbyService xmlns:u="urn:schemas-upnp-org:service:Abode-System...">
      <ErrorDescription>>%x%x%x%x%n</ErrorDescription>
      <ErrorCode>123"</ErrorCode>
    </u:DoUpdateUPnPbyService>
  </s:Body>
</s:Envelope>

Sending several such requests tailored to cause specific effects could enable attackers to achieve their desired outcome, compromising the security system.

To learn more about the specifics of this vulnerability, refer to the official CVE report: CVE-2022-35881

Mitigation and Prevention

Until a patch is released by Abode Systems, Inc., network administrators should ensure that their networks are secured from external unauthorized access. Implementing firewall rules and network segregation can help prevent an attacker from reaching the device hosting the iota All-In-One Security Kit.

Additionally, users are advised to regularly monitor the Abode Systems, Inc. GitHub repository and the vendor's official website for updates:

- Abode Systems iota All-In-One Security Kit
- Abode Systems, Inc. Official Website

Conclusion

CVE-2022-35881 highlights the importance of input sanitization when processing data from external sources, as well as the need for thorough security audits in software development. By understanding the cause and exploitation potential, developers can learn valuable lessons from this vulnerability and strive towards creating more secure applications.

Timeline

Published on: 10/25/2022 17:15:00 UTC
Last modified on: 10/27/2022 15:58:00 UTC