Understanding and fixing Curl and libcurl Vulnerabilities CVE-2023-38545 and CVE-2023-38546 a detailed analysis

CVE-2023-38546, CVE-2023-38545 curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management


CVE-2023-38546, curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management

What is curl, and which version is vulnerable

Curl, a robust command-line tool used for transferring data with URLs, is an indispensable asset for developers and cybersecurity professionals. Its versatility in supporting various protocols makes it a go-to tool for many. However, like a fortified castle with a hidden weak spot, libcurl and the software itself too has its vulnerabilities. Recently, two notable Common Vulnerabilities and Exposures (CVEs) were identified – CVE-2023-38545 and CVE-2023-38546. The latter, rated as high severity, affects both libcurl and the curl tool, marking a significant security concern. This blog aims to delve into these vulnerabilities and provide a guide on how to ensure your software version or library like libcurl is updated and secure. Please follow the step below and the verification to ensure your vulnerability management program and applications in your application security program are secure.

Understanding CVE-2023-38545

Curl is used by security and developers alike, even a robust tool like Curl and libcurl isn’t impervious to vulnerabilities. One such vulnerability, CVE-2023-38545, has been tagged with a high-severity rating, affecting both libcurl and the curl tool. Its disclosure marked a significant moment, stirring discussions in the cybersecurity community. A GitHub discussion led by one of the software maintainer unveiled the upcoming release of the software version 8.4.0 on October 11, aimed at patching this security flaw alongside a low-severity vulnerability, CVE-2023-38546. Although details regarding the affected version range were withheld for security reasons, the announcement serves as a call to action for users to update their Curl version promptly.

In a recent twitter conversation, the curl team has warned teams for the October 11 release but without disclosing additional information on which version is likely to be vulnerable. This to discourage early attacks

<blockquote class=”twitter-tweet”><p lang=”en” dir=”ltr”>We are cutting the release cycle short and will release curl 8.4.0 on October 11, including a fix for a severity HIGH CVE. Buckle up.</p>&mdash; daniel:// stenberg:// (@bagder) <a href=”https://twitter.com/bagder/status/1709103920914526525?ref_src=twsrc%5Etfw”>October 3, 2023</a></blockquote> <script async src=”https://platform.twitter.com/widgets.js” charset=”utf-8″></script>

CVE-2023-38545 curl in the wild, libcurl, curl,

Recently curl was in the spotlight due to the erroneous disclosure:  maintainers have been vocal about downplaying the risk associated with most vulnerabilities reported against curl  in the past (a recent example is the article CVE-2020-19909 is everything that is wrong with CVEs), nonetheless in this case he warned — adding, “buckle up.”

Detail of the curl vulnerability vulnerability CVE-2023-38545 and CVE-2023-38546

 libcurl, vulnerability, application security, vulnerability management

Update – Libcurl and chatgpt / LLM /BARD generated responses

The curl and other open source maintainers have been folded with requests through HackerOne and similar bug bounty platforms with bogus vulnerability reports. Be aware of wrong NVD information coming.

On the other hand NVD and curl library has a history of wrongly scored vulnerabilities like CVE-2022-42915 for more historical details refer to the Daniel Stenberg (one of the mantainer of curl) blog

How to upgrade to the Latest Stable Version: Curl 8.3.0 and new curl 8.4.0

As of now, the most recent stable release of software 8.3.0, which was unveiled on 2023-09-13. A significant number of downloads, precisely 88, are of this latest version, indicating a good rate of adoption within the user community. For those interested in exploring the code, the latest source code is accessible on GitHub, offering a glimpse into the engine room of this indispensable tool.

When is the next version of curl coming out?

The new release is scheduled for October the 11

Verifying Your Curl Version if is vulnerable to CVE-2023-38545 and CVE-2023-38546

Before diving into the update process, it’s crucial to ascertain the version of Curl you’re currently running. Here’s how:

  • Open your terminal.
  • Type in the command curl –version and hit enter.
  • The displayed output will indicate your Curl version.

Being cognizant of your software version is the first step towards ensuring a secure data transfer environment. If your version is prior to 8.4.0, consider updating to shield against the disclosed vulnerabilities.

macOS

  • Install Homebrew if you haven’t already, by running:
  • /bin/bash -c “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)”
  • Install the latest Curl version using Homebrew:
  • brew install curl
  • Update your PATH to prioritize the Homebrew version of Curl:
  • echo ‘export PATH=”/usr/local/opt/curl/bin:$PATH”‘ >> ~/.bash_profile
  • Source your updated ~/.bash_profile:
  • . ~/.bash_profile
  • Verify the update by checking the Curl version:

curl –version

Windows: 

  • Download the latest version from the official website and replace the old binaries.

Ubuntu/Debian:

  • sudoapt-get update && sudo apt-get install curl

Fedora:

  • sudo dnf upgrade cur

CentOS/RedHat:

  • sudo yum update curl

Each operating system has its own set of commands and procedures to update software. Ensure to backup any essential data and understand the update process to avoid any potential issues.

What is the exploitation data behind CVE-2023-38545 and CVE-2023-38546 In the wild

CVSS: TBD (assumed Critical)

CTI interest: Unknown

RCE Type Remote: Unknown (potential local authentication)

Availability: No

Status: Undisclosed

EPSS Score: – not registered –

Currently, there are 2673 systems with some version of curl exposed, but considering curl is embedded in every window, mac, linux version and container used like Amazon the spread and surface could be quite vaste

CVE-2023-38546, CVE-2023-38545 curl in the wild
CVE-2023-38546, CVE-2023-38545 curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management

How Phoenix Can Help

To manage and prevent such vulnerabilities, comprehensive security solutions are essential. Phoenix Security offers tools such as Vulnerability Management and Asset Management to help organisations quickly act on vulnerabilities like OpenSSH’s CVE-2023-38408.

Phoenix Security serves as a beacon for security professionals aiming to pinpoint the Curl vulnerability within their systems. It meticulously scans through your product, identifying instances where the libcurl vulnerability may be installed or nested within libraries. By leveraging Phoenix Security, you not only unravel the potential threats but also take a significant stride in vulnerability management, ensuring your application security remains unassailable against the Curl vulnerability.

The Asset Management tool, on the other hand, provides a comprehensive view of all assets in an organization’s network. This can help organizations understand which assets are vulnerable to CVE-2023-38408 and need immediate patching.

Conclusion

The discovery of the OpenSSH’s Agent Forwarding CVE-2023-38408 vulnerability underscores the continuous need for rigorous security measures and immediate response. Even robust systems like OpenSSH can harbor hidden vulnerabilities. Proactively rectifying such vulnerabilities through actions such as implementing patches and using comprehensive security solutions like those offered by Phoenix Security is critical to maintaining the integrity of digital assets.

Get in control of your Application Security posture and Vulnerability management

Previous Issues of Vulnerability Weekly




Francesco is an internationally renowned public speaker, with multiple interviews in high-profile publications (eg. Forbes), and an author of numerous books and articles, who utilises his platform to evangelize the importance of Cloud security and cutting-edge technologies on a global scale.

Discuss this blog with our community on Slack

Join our AppSec Phoenix community on Slack to discuss this blog and other news with our professional security team

From our Blog

The 2024 CWE Top 25 is out, and it’s no casual stroll through the vulnerability garden—especially when ransomware operators are busy planting path traversal exploits, while bug bounty hunters dig up endless injection flaws. In this blog, we examine the biggest risers, the most surprising dips, and the divergence between real-world exploit data and official CWE rankings. We’ll also reveal how AI-driven ASPM (Application Security Posture Management) and Phoenix Security’s contextual risk-based approach unite to help you focus on your most pressing threats. After all, not all flaws are created equal—some are simply more mischievous than others.
Francesco Cipollone
The 2024 CWE Top 25 list highlights the most dangerous software weaknesses. This article explores the methodology behind the list and how AI is improving threat detection. Discover how Application Security Posture Management (ASPM) and unified vulnerability management can help organizations address these critical threats.
Francesco Cipollone
Phoenix Security kicks off 2025 with recognition from Gartner Digital Markets through GetApp, solidifying its position as a leader in Application Security Posture Management (ASPM). Recognised for best customer success and support in ASPM, Phoenix Security empowers organisations with comprehensive, contextual vulnerability management and actionable cybersecurity solutions. With a user-friendly interface, robust real-time monitoring, and seamless risk prioritisation, the platform reduces alert fatigue while delivering precise remediation. As a cloud security leader, Phoenix Security continues to innovate, partnering with enterprises like LastPass and ClearBank to tackle the modern cybersecurity landscape head-on.
Francesco Cipollone
Discover how Phoenix Security is revolutionizing vulnerability management with its latest advancements in Application Security Posture Management (ASPM). From contextual deduplication to container version monitoring, this update empowers teams to prioritize vulnerabilities, streamline workflows, and strengthen application security. Dive into new integrations, enhanced asset details, and smarter risk management tools designed for modern security challenges.
Alfonso Eusebio
Phoenix Security’s Application Security Posture Management (ASPM) introduces Reachability Analysis and Contextual Deduplication to revolutionize vulnerability management. These features help security teams prioritize risks by correlating vulnerabilities from code to runtime, focusing on what’s exploitable. With contextual deduplication, Phoenix reduces vulnerability noise by up to 95%, ensuring only real threats are addressed. Stay ahead with 4D Risk Quantification, combining business criticality, network, and runtime reachability for smarter, more effective security.- Associate assets with multiple Applications and Environments – Mapping of vulnerabilities to Installed Software – Find Assets/Vulns by Scanner – Detailed findings Location information Risk-based Posture Management – Risk and Risk Magnitude for Assets – Filter assets and vulnerabilities by source scanner Integrations – BurpSuite XML Import – Assessment Import API Other Improvements – Improved multi-selection in filters – New CVSS Score column in Vulnerabilities
Alfonso Eusebio
Derek

Derek Fisher

Head of product security at a global fintech

Derek Fisher – Head of product security at a global fintech. Speaker, instructor, and author in application security.

Derek is an award winning author of a children’s book series in cybersecurity as well as the author of “The Application Security Handbook.” He is a university instructor at Temple University where he teaches software development security to undergraduate and graduate students. He is a speaker on topics in the cybersecurity space and has led teams, large and small, at organizations in the healthcare and financial industries. He has built and matured information security teams as well as implemented organizational information security strategies to reduce the organizations risk.

Derek got his start in the hardware engineering space where he learned about designing circuits and building assemblies for commercial and military applications. He later pursued a computer science degree in order to advance a career in software development. This is where Derek was introduced to cybersecurity and soon caught the bug. He found a mentor to help him grow in cybersecurity and then pursued a graduate degree in the subject.

Since then Derek has worked in the product security space as an architect and leader. He has led teams to deliver more secure software in organizations from multiple industries. His focus has been to raise the security awareness of the engineering organization while maintaining a practice of secure code development, delivery, and operations.

In his role, Jeevan handles a range of tasks, from architecting security solutions to collaborating with Engineering Leadership to address security vulnerabilities at scale and embed security into the fabric of the organization.

Jeevan Singh

Jeevan Singh

Founder of Manicode Security

Jeevan Singh is the Director of Security Engineering at Rippling, with a background spanning various Engineering and Security leadership roles over the course of his career. He’s dedicated to the integration of security practices into software development, working to create a security-aware culture within organizations and imparting security best practices to the team.
In his role, Jeevan handles a range of tasks, from architecting security solutions to collaborating with Engineering Leadership to address security vulnerabilities at scale and embed security into the fabric of the organization.

James

James Berthoty

Founder of Latio Tech

James Berthoty has over ten years of experience across product and security domains. He founded Latio Tech to help companies find the right security tools for their needs without vendor bias.

christophe

Christophe Parisel

Senior Cloud Security Architect

Senior Cloud Security Architect

Chris

Chris Romeo

Co-Founder
Security Journey

Chris Romeo is a leading voice and thinker in application security, threat modeling, and security champions and the CEO of Devici and General Partner at Kerr Ventures. Chris hosts the award-winning “Application Security Podcast,” “The Security Table,” and “The Threat Modeling Podcast” and is a highly rated industry speaker and trainer, featured at the RSA Conference, the AppSec Village @ DefCon, OWASP Global AppSec, ISC2 Security Congress, InfoSec World and All Day DevOps. Chris founded Security Journey, a security education company, leading to an exit in 2022. Chris was the Chief Security Advocate at Cisco, spreading security knowledge through education and champion programs. Chris has twenty-six years of security experience, holding positions across the gamut, including application security, security engineering, incident response, and various Executive roles. Chris holds the CISSP and CSSLP certifications.

jim

Jim Manico

Founder of Manicode Security

Jim Manico is the founder of Manicode Security, where he trains software developers on secure coding and security engineering. Jim is also the founder of Brakeman Security, Inc. and an investor/advisor for Signal Sciences. He is the author of Iron-Clad Java: Building Secure Web Applications (McGraw-Hill), a frequent speaker on secure software practices, and a member of the JavaOne Rockstar speaker community. Jim is also a volunteer for and former board member of the OWASP foundation.

Join our Mailing list!

Get all the latest news, exclusive deals, and feature updates.

The IKIGAI concept
x  Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
ShieldPRO