In this blog post, we will discuss in detail about the CVE-2021-21158, a potential security issue which was initially flagged for investigation, but later deemed to be out of scope for the designated CVE Numbering Authority (CNA).

We will first look at what this vulnerability was, the potential risks associated with it, code snippets to demonstrate the issue, and available exploits. We will then discuss why it was ultimately labeled as out of scope, which might provide valuable insight into how vulnerabilities are evaluated, and what factors contribute to the decision of them being deemed within or outside the scope of a specific organization.

As with any cybersecurity investigation, we always encourage our readers to view the original sources and contribute to the ongoing discussions with their observations and opinions. The links to these references are as follows:

1. CVE-2021-21158 Description
2. The CVE Assignment Process
3. CVE Numbering Authorities (CNAs)

CVE-2021-21158: The Security Issue

CVE-2021-21158 was reported to be a vulnerability in a popular software package, which could have reportedly allowed attackers to exploit a weakness in the input sanitization process. This flaw could potentially enable an attacker to take control of a web application or server - depending upon the specific circumstances - leading to significant security risks.

The code snippet below is a simplified example of this input sanitization weakness

# Example of vulnerable code
def unsafe_function(user_input):
    sanitized_input = user_input.replace("'", "")
    query = "SELECT * FROM data WHERE column = '" + sanitized_input + "'"
    return query

# Example of user input containing SQL injection
user_input = "'; DROP TABLE data; --"
resulting_query = unsafe_function(user_input)
print(resulting_query)

In the above code, the unsafe_function takes a user input and attempts to sanitize it by replacing single quotes with an empty string - an insufficient method of sanitizing input. If an attacker would provide a specially crafted payload like that in user_input, the resulting query would be capable of causing a SQL injection attack, potentially leading to data loss.

Exploit Details

While we refrain from providing explicit details on how to exploit such vulnerabilities, it is worth noting that attackers can leverage various tools and techniques in order to take advantage of the vulnerability exposed in CVE-2021-21158. SQL injection attacks, for instance, can be performed in both manual and automated manners. In this case, potential attackers may use automated tools to scan target applications and attempt to exploit any detected weaknesses.

The Issue's Rejection as Out of Scope

Upon further investigation by the designated CNA, it was concluded that the issue presented in CVE-2021-21158 was not within the scope of their responsibilities. This determination may have resulted from several factors such as:

1. _Affected Software_: The CNA might not have been responsible for the specific software/package that the vulnerability was found within.
2. _Nature of the Vulnerability_: The reported issue could have been viewed as being of low severity or low impact, or it could be considered a known issue that was previously addressed.
3. _Incorrect Analysis:_ The issue might not have been properly attributed to the software or component, or could have resulted from a third-party plugin or library that the CNA had no control over.

These factors, along with other undisclosed information, might have led the CNA to conclude that the CVE-2021-21158 was out of scope and hence not to be treated as a credible issue.

Conclusion

While CVE-2021-21158 ultimately turned out to be out of scope for the respective CNA, it provides an insight into the intricate process of vulnerability identification and evaluation. This case highlights the importance of organizations' due diligence in maintaining and following cybersecurity best practices and prompts both developers and users to be cautious of potential security flaws in various applications.

We hope that this post helped provide a clearer understanding of CVE-2021-21158, and we encourage our readers to stay updated on the constantly evolving landscape of cybersecurity.

Timeline

Published on: 01/17/2025 23:15:12 UTC