How secure coding guidelines evolve
Last week I was researching vulnerabilities in Java Spring to bring our secure coding guidelines up to date. I was going through the existing challenges on our platform and noticed a few on XSS through displaying url parameters in JSP pages. The incorrect code example would look something similar to the following:
<input type="text" name="username" value="${param.username}">
The correct solution was removing the URL parameter altogether and the description mentions that escaping the URL parameter the correct way is also safe.
Now, my job is to formulate the secure coding guideline in a way that is clear to developers and restricts them as little as possible while still writing secure code. In this case, I would prefer to let developers keep their intended functionality and recommend them to do it securely by escaping the URL parameter. This way, the code no longer contains a XSS vulnerability. The above example can be secured like this:
<input type="text" name="username" value="${fn:escapeXml(param.username)}">
And this was our secure coding guideline for a few days, until I stumbled on an OWASP page on expression language injection. This page describes how the Spring Expression Language (SpEL) can be abused for injection with some serious impact, including remote code execution. It was up to me to figure out if there could be cases where code adhering to our secure coding guideline can still be affected by this vulnerability. So I wrote a quick test application to evaluate SpEL expressions, and tested input with and without Xml escaping to see if I could find some scenarios that would not be caught. And I did, there are malicious expressions that do not contain any characters caught by XmlEscape. I published the working demo on our github, which you can find here.
And of course I updated our secure coding guideline which now reads: "Do not display or evaluate URL parameters using the Spring Expression Language (SpEL)."
The overall impact of this issue is High, for the following reasons: - An attacker could modify and invoke functionality on the application server. - Unauthorized access to data and functionality, as well as account hijacking and remote code execution. - Confidentiality, and Integrity concerns from a successful attack.
https://www.owasp.org/index.php/Expression_Language_Injection
Last week I was researching vulnerabilities in Java Spring to bring our secure coding guidelines up to date.
Application Security Researcher - R&D Engineer - PhD Candidate
Secure Code Warrior is here for your organization to help you secure code across the entire software development lifecycle and create a culture in which cybersecurity is top of mind. Whether you’re an AppSec Manager, Developer, CISO, or anyone involved in security, we can help your organization reduce risks associated with insecure code.
Book a demo
Application Security Researcher - R&D Engineer - PhD Candidate
Last week I was researching vulnerabilities in Java Spring to bring our secure coding guidelines up to date. I was going through the existing challenges on our platform and noticed a few on XSS through displaying url parameters in JSP pages. The incorrect code example would look something similar to the following:
<input type="text" name="username" value="${param.username}">
The correct solution was removing the URL parameter altogether and the description mentions that escaping the URL parameter the correct way is also safe.
Now, my job is to formulate the secure coding guideline in a way that is clear to developers and restricts them as little as possible while still writing secure code. In this case, I would prefer to let developers keep their intended functionality and recommend them to do it securely by escaping the URL parameter. This way, the code no longer contains a XSS vulnerability. The above example can be secured like this:
<input type="text" name="username" value="${fn:escapeXml(param.username)}">
And this was our secure coding guideline for a few days, until I stumbled on an OWASP page on expression language injection. This page describes how the Spring Expression Language (SpEL) can be abused for injection with some serious impact, including remote code execution. It was up to me to figure out if there could be cases where code adhering to our secure coding guideline can still be affected by this vulnerability. So I wrote a quick test application to evaluate SpEL expressions, and tested input with and without Xml escaping to see if I could find some scenarios that would not be caught. And I did, there are malicious expressions that do not contain any characters caught by XmlEscape. I published the working demo on our github, which you can find here.
And of course I updated our secure coding guideline which now reads: "Do not display or evaluate URL parameters using the Spring Expression Language (SpEL)."
The overall impact of this issue is High, for the following reasons: - An attacker could modify and invoke functionality on the application server. - Unauthorized access to data and functionality, as well as account hijacking and remote code execution. - Confidentiality, and Integrity concerns from a successful attack.
https://www.owasp.org/index.php/Expression_Language_Injection
Last week I was researching vulnerabilities in Java Spring to bring our secure coding guidelines up to date. I was going through the existing challenges on our platform and noticed a few on XSS through displaying url parameters in JSP pages. The incorrect code example would look something similar to the following:
<input type="text" name="username" value="${param.username}">
The correct solution was removing the URL parameter altogether and the description mentions that escaping the URL parameter the correct way is also safe.
Now, my job is to formulate the secure coding guideline in a way that is clear to developers and restricts them as little as possible while still writing secure code. In this case, I would prefer to let developers keep their intended functionality and recommend them to do it securely by escaping the URL parameter. This way, the code no longer contains a XSS vulnerability. The above example can be secured like this:
<input type="text" name="username" value="${fn:escapeXml(param.username)}">
And this was our secure coding guideline for a few days, until I stumbled on an OWASP page on expression language injection. This page describes how the Spring Expression Language (SpEL) can be abused for injection with some serious impact, including remote code execution. It was up to me to figure out if there could be cases where code adhering to our secure coding guideline can still be affected by this vulnerability. So I wrote a quick test application to evaluate SpEL expressions, and tested input with and without Xml escaping to see if I could find some scenarios that would not be caught. And I did, there are malicious expressions that do not contain any characters caught by XmlEscape. I published the working demo on our github, which you can find here.
And of course I updated our secure coding guideline which now reads: "Do not display or evaluate URL parameters using the Spring Expression Language (SpEL)."
The overall impact of this issue is High, for the following reasons: - An attacker could modify and invoke functionality on the application server. - Unauthorized access to data and functionality, as well as account hijacking and remote code execution. - Confidentiality, and Integrity concerns from a successful attack.
https://www.owasp.org/index.php/Expression_Language_Injection
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Secure Code Warrior is here for your organization to help you secure code across the entire software development lifecycle and create a culture in which cybersecurity is top of mind. Whether you’re an AppSec Manager, Developer, CISO, or anyone involved in security, we can help your organization reduce risks associated with insecure code.
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Application Security Researcher - R&D Engineer - PhD Candidate
Last week I was researching vulnerabilities in Java Spring to bring our secure coding guidelines up to date. I was going through the existing challenges on our platform and noticed a few on XSS through displaying url parameters in JSP pages. The incorrect code example would look something similar to the following:
<input type="text" name="username" value="${param.username}">
The correct solution was removing the URL parameter altogether and the description mentions that escaping the URL parameter the correct way is also safe.
Now, my job is to formulate the secure coding guideline in a way that is clear to developers and restricts them as little as possible while still writing secure code. In this case, I would prefer to let developers keep their intended functionality and recommend them to do it securely by escaping the URL parameter. This way, the code no longer contains a XSS vulnerability. The above example can be secured like this:
<input type="text" name="username" value="${fn:escapeXml(param.username)}">
And this was our secure coding guideline for a few days, until I stumbled on an OWASP page on expression language injection. This page describes how the Spring Expression Language (SpEL) can be abused for injection with some serious impact, including remote code execution. It was up to me to figure out if there could be cases where code adhering to our secure coding guideline can still be affected by this vulnerability. So I wrote a quick test application to evaluate SpEL expressions, and tested input with and without Xml escaping to see if I could find some scenarios that would not be caught. And I did, there are malicious expressions that do not contain any characters caught by XmlEscape. I published the working demo on our github, which you can find here.
And of course I updated our secure coding guideline which now reads: "Do not display or evaluate URL parameters using the Spring Expression Language (SpEL)."
The overall impact of this issue is High, for the following reasons: - An attacker could modify and invoke functionality on the application server. - Unauthorized access to data and functionality, as well as account hijacking and remote code execution. - Confidentiality, and Integrity concerns from a successful attack.
https://www.owasp.org/index.php/Expression_Language_Injection
Table of contents
Application Security Researcher - R&D Engineer - PhD Candidate
Secure Code Warrior is here for your organization to help you secure code across the entire software development lifecycle and create a culture in which cybersecurity is top of mind. Whether you’re an AppSec Manager, Developer, CISO, or anyone involved in security, we can help your organization reduce risks associated with insecure code.
Book a demoDownloadResources to get you started
AI Coding Assistants: A Guide to Security-Safe Navigation for the Next Generation of Developers
Large language models deliver irresistible advantages in speed and productivity, but they also introduce undeniable risks to the enterprise. Traditional security guardrails aren’t enough to control the deluge. Developers require precise, verified security skills to identify and prevent security flaws at the outset of the software development lifecycle.
Secure by Design: Defining Best Practices, Enabling Developers and Benchmarking Preventative Security Outcomes
In this research paper, Secure Code Warrior co-founders, Pieter Danhieux and Dr. Matias Madou, Ph.D., along with expert contributors, Chris Inglis, Former US National Cyber Director (now Strategic Advisor to Paladin Capital Group), and Devin Lynch, Senior Director, Paladin Global Institute, will reveal key findings from over twenty in-depth interviews with enterprise security leaders including CISOs, a VP of Application Security, and software security professionals.
Resources to get you started
Setting the Standard: SCW Releases Free AI Coding Security Rules on GitHub
AI-assisted development is no longer on the horizon — it’s here, and it’s rapidly reshaping how software is written. Tools like GitHub Copilot, Cline, Roo, Cursor, Aider, and Windsurf are transforming developers into co-pilots of their own, enabling faster iteration and accelerating everything from prototyping to major refactoring projects.
Close the Loop on Vulnerabilities with Secure Code Warrior + HackerOne
Secure Code Warrior is excited to announce our new integration with HackerOne, a leader in offensive security solutions. Together, we're building a powerful, integrated ecosystem. HackerOne pinpoints where vulnerabilities are actually happening in real-world environments, exposing the "what" and "where" of security issues.
Revealed: How the Cyber Industry Defines Secure by Design
In our latest white paper, our Co-Founders, Pieter Danhieux and Dr. Matias Madou, Ph.D., sat down with over twenty enterprise security leaders, including CISOs, AppSec leaders and security professionals, to figure out the key pieces of this puzzle and uncover the reality behind the Secure by Design movement. It’s a shared ambition across the security teams, but no shared playbook.
Developer-driven coding.
Securely.
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