In this long-read post, we will delve into a critical vulnerability that was identified by the Common Vulnerabilities and Exposures (CVE) program, specifically CVE-2023-3190. This vulnerability, which concerns improper encoding or escaping of output, was discovered in a popular GitHub repository, nilsteampassnet/teampass. Teampass, a widely-used software for managing passwords, was vulnerable to this issue in versions earlier than 3..9. In this post, we will explore this vulnerability in detail, discuss the potential consequences of exploitation, and share the mitigating steps one can take to protect themselves against potential threats.

Vulnerability Details

CVE-2023-3190 pertains to improper encoding or escaping of output in the Teampass password management software. Essentially, this issue allows attackers to inject and execute malicious code through the improper handling of specific characters.

The vulnerability stems from the use of certain PHP functions, such as htmlentities() and htmlspecialchars(), which seek to protect the software from harmful input by converting special characters into their HTML entity counterparts. Unfortunately, these functions can be bypassed under certain conditions, exposing users to potential harm.

Exploit and Code Snippets

By exploiting this vulnerability, an attacker can potentially gain unauthorized access to the target system. In most cases, the attacker would attempt to initiate a Cross-Site Scripting (XSS) attack by injecting malicioius JavaScript code into vulnerable sections where it is not escaped or encoded properly.

The following code snippet demonstrates a scenario in which an improper use of the htmlspecialchars() function renders the application susceptible to attack:

<?php
    $unsafe_input = '<script>alert("XSS vulnerability")</script>';
    // Using the 'htmlspecialchars' function with improper flags
    $safe_output = htmlspecialchars($unsafe_input, ENT_COMPAT);
    echo $safe_output;
?>

By not specifying the adequate flags (e.g., ENT_QUOTES, ENT_HTML5) in this case, the output is still vulnerable to an XSS attack, despite the use of htmlspecialchars().

Original References and Resources

The vulnerability was initially identified and reported by the security researchers at NIST, who published a detailed report on the issue. The full report can be found on the NIST National Vulnerability Database (NVD) site at the following link:

- CVE-2023-3190 - NIST NVD

In addition, more insights into the discovery, along with the discussion of the vulnerability, can be found on the GitHub repository where the Teampass software is hosted:

- Teampass GitHub Repository Issue #284

Mitigation and Recommendations

To address this vulnerability and protect users from potential attacks, the developers of Teampass released version 3..9, which includes a patch addressing CVE-2023-3190. It is strongly recommended that all users of the affected Teampass versions immediately update their software to the latest version. To do so, simply head over to the official Teampass GitHub repository and follow the update instructions:

- Teampass GitHub Repository Release 3..9

Moreover, it is advisable to keep the following best practices in mind when working with PHP and handling user input:

- Always use the latest version of the PHP software, which includes the most up-to-date security measures.
- Employ proper encoding and escaping functions when handling user input, especially when outputting to an HTML or JavaScript context.
- Make use of Content Security Policy (CSP) headers to limit the vectors through which XSS attacks can be conducted.

Conclusion

CVE-2023-3190, a critical vulnerability present in earlier versions of the Teampass password management software, has been successfully patched in version 3..9. Since the potential consequences of this vulnerability can be severe, it is vital that users take the necessary steps to protect themselves and their systems by updating to the latest version. Stay vigilant, stay informed, and stay secure.

Timeline

Published on: 06/10/2023 09:15:00 UTC
Last modified on: 06/15/2023 18:40:00 UTC