What is Remote Code Execution (RCE) ?

Remote code execution(RCE) is an arbitrary code running on a remote system using security vulnerability and connecting it to a private or public network. Physical access is not required. The RCE can have severe consequences of Malware, loss of data, Service disruption, and ransomware deployment. The RCE vulnerability is exploited by the attacker without any access to the victim's system. When we download malicious software or application then it gives rise to the use of RCE by cyber attackers. The OWASP has recognized Remote procedure code as a vulnerability for cyber attacks.

Overview

Definition

Remote Code Execution is a remote attack on a computer by executing malicious code. The Remote code execution is arbitrary. It seeks vulnerability or security flaws of software or applications of targeted systems.

The impact of the RCE

• The attacker penetrates to RCE vulnerabilities of the network with initial access to run the command to install malware or any other goal.

• The sensitive data from vulnerable device exposure using direct commands or malware.

• The operation of the application or system is disrupted by running the code of the attacker. This type of attack is also known as Denial of Service.

• Ransomware a malware used to deploy on users to deny access to computer files until a ransom is paid. The RCE vulnerability provides an attacker access so making it the most critical type of vulnerability.

• Another type can be Cryptomining used to mine cryptocurrency by compromising computational resources to gain financial benefit.

In such a manner various dangerous attacks can be done to control comprised devices using RCE vulnerability. Ransomware is the most dangerous one in cyber attacks.

Techniques of Remote Code executive

The major two types comprise to perform RCE as follows,

Remote Code Evaluation

When users allow given a username which may be malicious code enabling attackers to attack the application. The attacker influences input evaluation using malicious programming languages. Hence code evaluation occurs from user input.

Stored code Evaluation

The difference between remote code evaluation is that it utilizes interpreter file parsing rather than programming language function. The flaws in validating proper files and websites contain upload functionality.

For example − Each user has specific language variable settings stored in a config file. The attacker injects code into the config file by modifying language parameters and executing arbitrary commands.

Different ways to achieve RCE

Attack through injection attack

SQL queries are commands as user input in any website or application. As the SQL query is used as a command and gets the input to design an attack running on a vulnerable system using arbitrary code.

Attack through Deserialization

Several pieces of data are in a single string to communicate using serialization. The deserialization program interprets serialized data by formatting the input from the user.

Out of Bound Write

Data get stored in fixed chunks which attackers attack executing code i.e. malicious code to write outside the buffer for getting the input. Memory allocation possesses the vulnerability that an attacker uses.

Example of RCE

Wannacry is a popular example of RCE and it is ransomware affecting thousands of computers worldwide. The server is infected using DoublePulsar or EternalBlue which install wannacry ransomware and also infect client machines comprising thousands of computers.

RCE Attack detection and mitigation

Sanitizing the user input

Before allowing the user input to be utilized by the application which prevents various attacks undergo validating and sanitizing user-supplied input. The deserialization and injection loophole used for RCE attack. For eg: SQL injection.

Memory management security

The buffer overflows are the key attackers use to exploit. Regular scans of vulnerability should be run to detect such error

Inspection of traffic

The co-operate system attacked by manipulating the network traffic and injecting code using the vulnerability. A web application firewall effectively protects from malicious threats as it monitors and protects the endpoints of network traffic.

Control Access

Network segmentation, access management, and zero trust policies, etc are a few controls that can help secure the attacker from gaining the first access. The RCE vulnerability gives expand access and more dangerous attack deployed by foothold on the target network of the enterprise. The user permissions need to be limited by access control lists.

Prevention steps from RCE

• A large amount of data should be sanitized.

• Use safe practices to secure the web or file uploads.

• Any user input is passed inside callbacks or evaluation functions.

• The special characters or functions are to be blacklisted.

• Snort can detect suspicious traffic and detect intrusions.

• RCE attacks can be prevented by buffer overflow protection that won't access vulnerability fast.

Conclusion

Access to protected data, escalating privileges, or gaining unauthorized access gives rise to several attacks. These flaws in the application and network are to be secured. RCE vulnerabilities can be prevented by implementing security while using the system or applications.