Malicious Software

Malicious software is code or software intentionally designed to harm systems, steal information, disrupt operations, bypass security controls, or provide unauthorized access. It includes threats such as ransomware, spyware, trojans, worms, viruses, backdoors, rootkits, keyloggers, and credential theft tools.

Malware is simply the shortened term for malicious software. Both terms refer to software or code created for harmful or unauthorized purposes, such as data theft, system disruption, unauthorized monitoring, fraud, or persistence inside an environment.

Common types include viruses, worms, trojans, ransomware, spyware, adware, rootkits, backdoors, keyloggers, botnet agents, droppers, downloaders, and fileless malware. These categories often overlap because attackers may combine multiple techniques in a single campaign.

Malicious software can enter through phishing emails, unsafe downloads, compromised websites, exposed services, unpatched vulnerabilities, stolen credentials, removable media, malicious scripts, insecure remote access, or compromised third-party software. Weak configuration and excessive permissions can make infections spread faster.

Organizations reduce malware risk by maintaining secure configurations, patching vulnerabilities, filtering email and web traffic, restricting administrative access, training users, monitoring endpoints, scanning files, controlling software installation, segmenting networks, and validating backups. Prevention should be layered because no single control blocks every attack.

Useful controls include endpoint protection, application allowlisting, email security gateways, web filtering, intrusion detection, vulnerability scanning, centralized logging, behavioral analytics, sandboxing, file integrity monitoring, least-privilege access, and alert triage procedures. Detection should cover endpoints, servers, cloud workloads, identities, and network activity.

A company should contain affected systems, preserve evidence, identify the malware type and entry point, assess data and operational impact, remove the malicious code, reset exposed credentials, restore trusted systems, communicate with stakeholders as required, and document lessons learned. Recovery should include root-cause analysis and control improvements.

Ransomware is a form of malicious software that typically encrypts data, disrupts access, or threatens disclosure to pressure the victim into paying a ransom. Unlike many malware types that focus on stealth, ransomware often creates an immediate operational crisis and requires strong backup, response, and recovery planning.

Auditors commonly look for documented policies, assigned control ownership, endpoint protection coverage, alert records, malware scan results, patching evidence, incident response procedures, backup testing records, security awareness completion, access control reviews, and examples of remediation for detected infections or high-risk findings.

Framework-neutral GRC expectations usually require organizations to identify malware risks, implement preventive and detective controls, monitor security events, respond to incidents, maintain recovery capability, review control effectiveness, and retain evidence. The exact requirements depend on applicable regulations, customer obligations, contractual commitments, and internal risk tolerance.