Data at Risk Due to Microsoft Zero-Day RCE Exploit

by | Aug 22, 2023

Microsoft has revealed information about a zero-day RCE exploit which can lead to vulnerable computers and stolen data. First discovered on July 11th, Microsoft views it as high risk with a CVSS score of 7.5, noting it could lead to a major loss of confidential data. While it’s hazardous, it requires more than the hacker’s actions to take effect, limiting its damage potential. Like with many types of threats that we’ve discussed ongoing, this zero-day RCE attack only works if the user downloads and receives the infected file.

What Is Remote Code Execution (RCE)?

Remote Code Execution (RCE) is a type of cyberattack that allows hackers to use remote use commands, scripts, or malicious code on a target’s system without proper authorization. That can occur when an attacker exploits vulnerabilities in the system’s software, allowing them to bypass security measures and gain control over the system. RCE is considered a severe threat, as it can lead to unauthorized access to sensitive data, system manipulation, or even a complete takeover of the targeted system.

Who’s Impacted by the Zero-Day RCE Exploit?

Users and organizations utilizing Microsoft Office are at risk from the RCE (Remote Code Execution) exploit. Those that haven’t applied the latest patches are still vulnerable. The RCE exploits allowed threat actors, such as the RomCom hacking group, to create specially crafted documents that could bypass security features and perform remote code execution.

Hackers took advantage of this flaw to bypass some security features, leading to files being opened without displaying a security warning. This threat impacts anyone who uses Microsoft Office, and we encourage everyone to confirm their software is updated to the latest version.

Why Zero-Day RCE Exploits Are a Challenge

Zero-Day Exploits refer to vulnerabilities in software that are unknown to those responsible for patching or fixing the software. These are especially hard to defend against, even for corporations as large as Microsoft, since the issue is only known after it’s been abused. These vulnerabilities are called “zero-day” because developers have zero days to fix the problem once due to their dangerous nature. Attackers can use zero-day exploits to gain unauthorized access to a system, steal sensitive information, or launch other malicious activities.

The challenge of preventing zero-day RCE exploits lies in the complexity of modern software and the ever-evolving nature of security threats. Vulnerabilities that lead to remote code execution can be found in various components, including web applications, operating systems, and network protocols. For this attack specifically, infected documents were used to gain access.

How To Protect Yourself from Zero-Day RCE Exploits

Protecting yourself from zero-day RCE exploits requires a mixed approach that combines proactive measures, continuous monitoring, and timely response. Here’s what you can do:

1. Regularly Update Software

As seen with the Microsoft Office and .NET vulnerabilities, software vendors often release patches to fix known vulnerabilities, including zero-day exploits. Regularly updating your software ensures you have the latest security patches, reducing the risk of exploitation.

2. Employ Security Tools

Utilize antivirus software, firewalls, and intrusion detection systems that can identify and block suspicious activities. These tools can provide an additional layer of defense against unknown threats, including zero-day RCE exploits.

3. Practice Safe Browsing and Email Habits

Be cautious with emails from unknown sources and avoid downloading attachments or clicking links that seem suspicious. The RCE exploit in Microsoft Office, for example, was triggered by specially crafted documents, so being vigilant about what you open can prevent such attacks.

4. Limit User Access

Limiting user permissions to only what’s necessary can minimize the potential damage from an RCE attack. If an attacker gains access to a system with limited permissions, their ability to execute malicious code or move laterally within the network may be restricted.

5. Monitor Systems and Networks

Continuous monitoring of systems and networks can help detect unusual activities that may indicate an RCE exploit. Early detection can lead to a quicker response, minimizing potential damage.

6. Educate and Train Staff

Training employees to recognize and report potential security threats can be a vital line of defense in organizational settings. Awareness of the risks associated with RCE and zero-day exploits can lead to more cautious behavior.

7. Collaborate with Security Professionals

If possible, consult with cybersecurity experts to assess your system’s vulnerabilities and implement necessary security measures. Collaboration with professionals can provide insights tailored to your specific needs and risks.

8. Have an Incident Response Plan

Prepare a plan for how to respond if a zero-day RCE exploit is detected. A well-structured response plan can minimize the impact and help in the recovery process.

Protecting yourself from zero-day RCE exploits is an ongoing process that requires vigilance, proactive measures, and a willingness to adapt to the ever-changing landscape of cybersecurity threats. By implementing strategies like these, individuals and organizations can significantly reduce the risk of falling victim to these sophisticated and potentially devastating attacks.

Don’t Leave Yourself Exposed to RCE Exploits

The Microsoft Office RCE exploit should already be fixed for those with auto-updates enabled. That’s why routine software patching is an important part of any cybersecurity strategy. Even if the software continues to work fine as-is, the more outdated the version, the higher chance it’s vulnerable to cyber threats. 

It’s also vital to use good cybersecurity habits with anything you do. That means being careful about what links you click on, what files you download, and what information you share without confirming someone’s identity. Cybercriminals are always looking for new ways to trick people. Even something as innocent as a text document or a PDF can be infected. When in doubt, forward anything suspicious to your IT team.

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