When a major security incident makes the headlines, Remote Code Execution (RCE) is often involved somewhere in the story. The recent discovery of an RCE vulnerability in Redis servers demonstrated this perfectly, allowing attackers to run arbitrary commands and potentially leading to complete system compromise.
It’s one of those vulnerabilities that attackers are quick to take advantage of. Once they can run code on a system they don’t own, the situation can escalate quickly. Let’s see what Remote Code Execution involves and how to prevent it.
Understanding Remote Code Execution
Remote Code Execution (RCE) allows attackers to run their own code on someone else’s system. When this happens, the attacker can typically do anything the system itself can do. That may mean accessing sensitive data, creating new privileged accounts, deploying ransomware, or using the compromised machine to move deeper into the network.
It’s important to understand that RCE is usually the result of another underlying vulnerability, not a standalone flaw. Issues such as command injection, insecure deserialization, misconfigurations, or even weaknesses in third‑party components can all create the conditions that make remote code execution possible.
Supply chain visibility is really crucial because if a dependency contains an RCE flaw, every application using it inherits that risk and could be exposed to a supply chain attack.
The reason RCE is so serious is the control it grants, as the attacker no longer needs to authenticate or guess passwords. In fact, RCE vulnerabilities often receive some of the highest CVSS scores.
Remote code execution does not require physical access to the target system, making it especially dangerous. All attackers need is a network connection and a vulnerable system. The attacker’s ability to exploit these vulnerabilities determines the extent of damage they can cause, including bypassing security measures and escalating privileges.
Types of Remote Code Execution Vulnerabilities
Most remote code execution attacks exploit flaws elsewhere in an application. These underlying issues give attackers the opportunity to execute arbitrary code if exploited.
Remote Code Execution vulnerabilities have several forms, each having its own challenges for defenders and opportunities for attackers. Knowing the different types of RCE vulnerabilities is essential for developing robust security measures and reducing the risk of remote code execution attacks.
Here are some of the most frequent sources of RCE:
Injection Vulnerabilities
RCE often starts with code injection, where untrusted input reaches a part of the system that executes commands. A typical example is command injection, where user input goes directly to a system shell. Without proper validation, attackers can run arbitrary commands on the server.
Also, XSS is basically unauthorized code execution in the victim’s browser. Other types of vulnerabilities that can lead to code execution include Server-Side Template Injection (SSTI) and even SQL injection. Thinking of RCE this way makes it easier to find insecure patterns and prevent security problems.
Another factor to consider is the use of embedded interpreters (e.g., Python, Lua). Embedding a scripting engine lets applications be flexible, but it also opens a direct path to RCE if untrusted input reaches the interpreter.
Deserialization Vulnerabilities
Some web applications serialize data to store or transfer it, then deserialize it later. If the data being deserialized can be controlled or modified by an attacker, they can craft payloads that execute code during the deserialization process. This can lead to complete control of the application or server.
Buffer Overflows
If a program writes more data into memory than it should, it can overwrite nearby memory structures. With careful manipulation, attackers use this to inject and run arbitrary code. This is found more in native and legacy software; however, it remains a vector.
Why RCE Leads to Serious Incidents
When an attacker gains the ability to execute commands remotely, they can:
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Deploy malware, including ransomware, to further compromise the environment.
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Steal or read sensitive information.
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Install backdoors or malware for persistent access.
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Move laterally to other systems in the network.
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Disable security tools or modify system configurations.
The impact can be huge. Since March 2023, the Akira ransomware group has exploited RCE vulnerabilities to affect over 250 organizations. The group has actively targeted critical RCE flaws in enterprise systems, demonstrating how quickly threat actors can weaponize them.
Many major breaches originated from a single RCE vulnerability on an internal or externally exposed service. Even strong network segmentation or perimeter controls can fail if one internal service has a flaw that allows remote code execution.
Learning from Redis
As mentioned earlier, a recent Redis attack shows how RCE vulnerabilities can hide in plain sight. Last month, researchers disclosed RediShell, a use-after-free vulnerability in Redis’s Lua scripting engine that had existed undetected for 13 years.
The flaw allows authenticated attackers to send a specially crafted Lua script that escapes the Redis environment and run any command they want on the host machine. This means complete control, not just over Redis data, but over the entire server.
From there, the attack follows a familiar RCE pattern, including stealing credentials, deploying malware, exfiltrating data, or moving laterally across the network. It might only start as database access, but could become a complete system compromise.
How to Reduce the Risk of Remote Code Execution
While no single step eliminates RCE risk entirely, several practices can significantly reduce it.
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Always validate and sanitize user input to stop code injection and other risks.
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Avoid running system commands directly whenever possible.
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Limit or disable dynamic module loading to reduce attack surfaces.
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Keep internal services and admin interfaces hidden from external access.
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Apply least-privilege principles for services, containers, and cloud roles.
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Conduct regular code reviews and hands-on security testing.
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Follow secure coding best practices, including code analysis.
Even small changes can prevent attackers from gaining access, such as adjusting default configurations or removing unnecessary service exposure.
Learn to Prevent RCE with SecureFlag
Remote code execution is best understood through real-world practice rather than theory alone. SecureFlag provides hands-on secure coding training for developers to detect and prevent security vulnerabilities, including RCE.
This includes training labs covering scenarios such as:
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Identifying and fixing RCE vulnerabilities in code.
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Cloud and container security practices.
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Secure Redis configuration and data protection.
Working in realistic, guided environments, teams experience how attacks unfold and what effective prevention looks like in practice, reducing risk before issues reach production.
If your organization wants to strengthen its security capabilities and reduce the likelihood of vulnerabilities, such as Remote Code Execution, SecureFlag can help.
