Adobe Acrobat Reader Vulnerabilities Patched: Critical Arbitrary Code Execution Flaws Addressed

Adobe has recently addressed critical vulnerabilities in Adobe Acrobat Reader, as highlighted in the NCSC-2025-0084 advisory. These vulnerabilities, which include out-of-bounds read and Use After Free flaws, could allow attackers to execute arbitrary code on affected systems. This article delves into the technical details of the vulnerabilities, their potential impact, and the steps users can take to mitigate risks.

TL;DR: Key Takeaways

Vulnerabilities: Out-of-bounds read and Use After Free flaws in Adobe Acrobat Reader.
Impact: Arbitrary code execution, leading to unauthorized system access and control.
Exploitation: Requires user interaction, such as opening a malicious file.
Patch Status: Adobe has released updates to address these vulnerabilities.
Audience Relevance: Critical for Red Teamers, Blue Teamers, SOC Analysts, and System Administrators.

Technical Overview of the Vulnerabilities

The vulnerabilities identified in Adobe Acrobat Reader, as detailed in the NCSC-2025-0084 advisory, are particularly concerning due to their potential for arbitrary code execution. Here’s a breakdown of the flaws:

Out-of-Bounds Read: This vulnerability occurs when the software reads data beyond the bounds of a buffer. In the context of Adobe Acrobat Reader, this could allow an attacker to access sensitive memory areas, potentially leading to information disclosure or further exploitation.
Use After Free: This flaw arises when the software continues to use a memory pointer after it has been freed. In Adobe Acrobat Reader, this could be exploited to execute malicious code by manipulating memory allocations.

Both vulnerabilities require user interaction, such as opening a malicious PDF file, to be exploited. This makes phishing campaigns a likely vector for attackers.

Exploitation and Impact

The exploitation of these vulnerabilities could have severe consequences:

Arbitrary Code Execution: Attackers could execute malicious code with the privileges of the logged-in user, potentially leading to full system compromise.
Unauthorized Access: Sensitive data could be accessed or exfiltrated.
System Control: Attackers could gain persistent access to the system, enabling further malicious activities.

The NCSC advisory emphasizes that these vulnerabilities are rated as Medium to High (M/H) in terms of severity, indicating a significant risk to organizations and individual users alike¹.

Relevance to Security Professionals

For Red Teamers, these vulnerabilities present an opportunity to test organizational defenses against sophisticated phishing campaigns and file-based exploits. Crafting Proof of Concept (PoC) exploits for these flaws could help in simulating real-world attack scenarios.

For Blue Teamers and SOC Analysts, understanding the technical details of these vulnerabilities is crucial for developing effective detection and mitigation strategies. Monitoring for suspicious PDF files and implementing strict file execution policies can help reduce the risk of exploitation.

System Administrators should prioritize applying the latest patches from Adobe to mitigate these vulnerabilities. Additionally, educating users about the risks of opening untrusted files is essential.

Remediation Steps

Adobe has released updates to address these vulnerabilities. Here are the recommended steps to secure your systems:

Update Adobe Acrobat Reader: Ensure that all instances of Adobe Acrobat Reader are updated to the latest version. Refer to Adobe’s security bulletin for detailed instructions².
Implement Application Whitelisting: Restrict the execution of unauthorized applications, including potentially malicious PDF files.
User Education: Train users to recognize and avoid phishing attempts, particularly those involving suspicious email attachments.
Monitor for Exploitation Attempts: Use endpoint detection and response (EDR) tools to monitor for signs of exploitation, such as unusual process behavior or memory manipulation.

Conclusion

The NCSC-2025-0084 advisory highlights the importance of promptly addressing vulnerabilities in widely used software like Adobe Acrobat Reader. By understanding the technical details of these flaws and implementing the recommended mitigation steps, organizations can significantly reduce their risk exposure.

For security professionals, this advisory serves as a reminder of the ever-present threat posed by file-based exploits and the need for robust defensive measures.