How Does It Work?
RCE vulnerabilities allow an attacker to execute arbitrary code on a remote device. An attacker can achieve RCE in a few different ways, including:
- Injection Attacks: Many different types of applications, such as SQL queries, use user-provided data as input to a command. In an injection attack, the attacker deliberately provides malformed input that causes part of their input to be interpreted as part of the command. This enables an attacker to shape the commands executed on the vulnerable system or to execute arbitrary code on it.
- Deserialization Attacks: Applications commonly use serialization to combine several pieces of data into a single string to make it easier to transmit or communicate. Specially formatted user input within the serialized data may be interpreted by the deserialization program as executable code.
- Out-of-Bounds Write: Applications regularly allocate fixed-size chunks of memory for storing data, including user-provided data. If this memory allocation is performed incorrectly, an attacker may be able to design an input that writes outside of the allocated buffer. Since executable code is also stored in memory, user-provided data written in the right place may be executed by the application.
Examples Of RCE Attacks
RCE vulnerabilities are some of the most dangerous and high-impact vulnerabilities in existence. Many major cyberattacks have been enabled by RCE vulnerabilities, including:
- Log4j: Log4j is a popular Java logging library that is used in many Internet services and applications. In December 2021, multiple RCE vulnerabilities were discovered in Log4j that allowed attackers to exploit vulnerable applications to execute cryptojackers and other malware on compromised servers.
- ETERNALBLUE: WannaCry brought ransomware into the mainstream in 2017. The WannaCry ransomware worm spread by exploiting a vulnerability in the Server Message Block Protocol (SMB). This vulnerability allowed an attacker to execute malicious code on vulnerable machines, enabling the ransomware to access and encrypt valuable files.
The RCE Threat
RCE attacks are designed to achieve a variety of goals. The main difference between any other exploit to RCE, is that it ranges between information disclosure, denial of service and remote code execution.
Some of the main impacts of an RCE attack include:
- Initial Access: RCE attacks commonly begin as a vulnerability in a public-facing application that grants the ability to run commands on the underlying machine. Attackers can use this to gain an initial foothold on a device to install malware or achieve other goals.
- Information disclosure: RCE attacks can be used to install data-stealing malware or to directly execute commands that extract and exfiltrate data from the vulnerable device.
- Denial of Service: An RCE vulnerability allows an attacker to run code on the system hosting the vulnerable application. This could allow them to disrupt the operations of this or other applications on the system.
- Cryptomining: Cryptomining or cryptojacking malware uses the computational resources of a compromised device to mine cryptocurrency. RCE vulnerabilities are commonly exploited to deploy and execute cryptomining malware on vulnerable devices.
- Ransomware: Ransomware is malware designed to deny a user access to their files until they pay a ransom to regain access. RCE vulnerabilities can also be used to deploy and execute ransomware on a vulnerable device.
While these are some of the most common impacts of RCE vulnerabilities, an RCE vulnerability can provide an attacker with full access to and control over a compromised device, making them one of the most dangerous and critical types of vulnerabilities.
Mitigation And Detection Of RCE Attacks
RCE attacks can take advantage of a range of vulnerabilities, making it difficult to protect against them with any one approach. Some best practices for detecting and mitigating RCE attacks include:
- Input Sanitization: RCE attacks commonly take advantage of injection and deserialization vulnerabilities. Validating user input before using it in an application helps to prevent many types of RCE attacks.
- Secure Memory Management: RCE attackers can also exploit issues with memory management, such as buffer overflows. Applications should undergo vulnerability scanning to detect buffer overflow and other vulnerabilities to detect and remediate these errors.
- Traffic Inspection: As their name suggests, RCE attacks occur over the network with an attacker exploiting vulnerable code and using it to gain initial access to corporate systems. An organization should deploy network security solutions that can block attempted exploitation of vulnerable applications and that can detect remote control of enterprise systems by an attacker.
- Access Control: An RCE attack provides an attacker with a foothold on the enterprise network, which they can expand to achieve their final objectives. By implementing network segmentation, access management, and a zero trust security strategy, an organization can limit an attacker’s ability to move through the network and take advantage of their initial access to corporate systems.
Check Point firewalls enable an organization to detect and prevent attempted exploitation of RCE vulnerabilities via injection or buffer overflow attacks. Placing applications behind a firewall helps to dramatically reduce the risk that they post to the organization.
Check Point can also support organizations working to remediate an RCE vulnerability or have suffered an RCE attack. If you need help addressing an RCE or other cyberattack, contact Check Point support.