In recent years, concerns regarding security have become more significant than ever as we have been growing increasingly interconnected. One area that these vulnerabilities are especially prevalent is within the realm of mobile devices and operating systems. The OpenHarmony project attempts to answer these concerns by providing an open-source, versatile operating system that promises high security standards. However, no system is perfect, and vulnerabilities can sometimes slip through the cracks - as is the case with CVE-2022-43449.

CVE-2022-43449 pertains to an arbitrary file read vulnerability found in OpenHarmony-v3.1.2 and prior versions. This vulnerability affects the download_server component. Local attackers can exploit this vulnerability by installing a malicious application on the device that can reveal any file from the filesystem that is accessible to the download_server service, which itself runs with UID 100.

In this blog post, we will cover a detailed breakdown of the vulnerability along with an example of a potential exploit and mitigation techniques that can be employed to address the issue.

Vulnerability Details

The vulnerability in question exists within the download_server component, which allows devices to serve files over a network connection. The download_server component is designed to securely serve files, but a weak point in its implementation allows an attacker to gain access to arbitrary files on the system.

The key issue lies in the insufficient validation of user-supplied input when requesting a file download. As a result, an attacker could potentially craft a malicious download request that bypasses the server's intended access controls, essentially allowing the attacker to access files that should be off-limits.

Exploiting this vulnerability requires local access to the device – a malicious application must be installed first in order to exploit the issue. However, if successful, the attacker can gain unauthorized access to sensitive information and other files on the device.

Exploit Example

To demonstrate how a local attacker could exploit this vulnerability, let's walk through a sample attack scenario:

First, the attacker would need to install a malicious application on the victim's device. This can be accomplished through a drive-by download attack or by social engineering the victim into installing the application themselves.

Once the malicious application is running on the device, it can take advantage of the vulnerable download_server component by sending a crafted download request that includes an arbitrary file path. For example:

GET /download?file=/data/sensitive_info.txt HTTP/1.1
Host: vulnerable_download_server

In this case, the malicious application is requesting a download of /data/sensitive_info.txt. The download_server should reject this request due to access control policies but, due to the vulnerability, it incorrectly processes the request and returns the contents of the arbitrary file.

By exploiting this vulnerability, attackers can potentially access sensitive information, system files, or other data that should be securely protected.

Mitigations

There are several potential mitigations that can be implemented in order to address this vulnerability:

- Update to the latest version of OpenHarmony: It's important to always keep your software up to date, as patches and new versions often come with security enhancements and bug fixes. Where possible, update to a version of OpenHarmony that has fixed this vulnerability.
- Patch the affected component: If updating is not an option, consider patching the vulnerable download_server component. Additional input validation is required to ensure that only the intended files can be accessed.
- Restrict permissions: Limit application access and permissions on the device to reduce possible attack vectors. This can involve revoking unnecessary permissions from installed applications and avoiding installing applications from untrusted sources.

Conclusion

The CVE-2022-43449 arbitrary file read vulnerability in OpenHarmony-v3.1.2 and prior versions presents a significant security risk if left unaddressed. Local attackers can leverage this vulnerability to access sensitive files, system components, and other data that should be secured.

Developers and users alike should be diligent in updating their software and ensuring that adequate safeguards are in place to maintain the integrity of their systems. By understanding the implications of CVE-2022-43449 and taking necessary precautions, we can work towards improving the security of our digital world.

Further resources

- OpenHarmony Project: https://www.openharmony.io/
- CVE-2022-43449 Official Entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-43449
- CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'): https://cwe.mitre.org/data/definitions/22.html

Timeline

Published on: 11/03/2022 20:15:00 UTC
Last modified on: 11/07/2022 02:18:00 UTC