Ransomware Detection: Common Signs and 3 Detection Techniques

The Need for Early Detection

Early detection in cyberattacks is very important. The earlier incidents are stopped in the attack chain, the less likely an attacker is to steal sensitive data or compromise organizational systems.

Early detection of ransomware attacks is more important than any other malware, because the damage is irreversible. If ransomware encrypts data that is not securely backed up, recovery may not be possible, even if the victim pays the ransom. To minimize damage, it is important to prevent ransomware infection before they start encrypting data.

As ransomware advances, early detection becomes more important. Newer ransomware variants steal sensitive company data before being encrypted. If ransomware is detected before data theft occurs, companies will avoid potentially costly and reputationally harmful data breaches.

Related content: Read our guide to ransomware prevention

Common Signs of Ransomware

While different ransomware variants implement the attack in different ways, most have several things in common:

• Ransomware scans a system and disables or removes processes, services, and software that can help detect or recover from the attack, before beginning the encryption phase.
• Ransomware deletes system backups, recovery partitions, and shadow copies to prevent potential data recovery.
• Ransomware disables and clears the system event log.
• After the above preparation steps, selected file systems containing business-critical data are encrypted.
• Finally, ransomware leaves a “ransom note” with the malicious attacker’s contact information so the victim can pay the ransom to release their data.

The specific files encrypted will depend on the specific ransomware variant, parameters passed to the ransomware binary to customize its operation for certain victims or campaigns, and pre-configured features of the ransomware program. These could be hardcoded into the ransomware binary itself or added as scripts or utilities packaged with the ransomware.

Most types of ransomware contain configurations that specify whether to include or exclude:

• Certain files based on a file extension, file type, or other pattern matching techniques.
• File system directories – for example, the ransomware might be instructed to encrypt C:Users and avoid encrypting C:Windows.
• Remote network file shares – this will allow the ransomware to encrypt any file share accessible by the infected device.

Ransomware Detection Techniques

The following are the most common techniques for detecting ransomware on an infected device.

Signature-based Detection

Signature-based ransomware detection compares ransomware binary hashes to known malware signatures. This enables fast, static analysis of files in the environment. Security platforms and antivirus software capture data from executables to determine whether they are ransomware or approved executables. Most modern antivirus solutions have this capability – when they scan the local environment for malware, they can detect known ransomware variants.

Signature-based ransomware detection technology is a first line of defense. It helps detect known threats, but it is largely unable to identify new ransomware strains. In addition, attackers update and permutate malware files to avoid detection. Even adding just one byte to a file creates a new hash and reduces the likelihood of malware detection.

Still, signature-based detection helps identify outdated ransomware samples and known good files (for example, common business applications), ruling out the possibility that they are malware. It can protect against ordinary ransomware campaigns, but not sophisticated, targeted ransomware campaigns.

Detection Based on Data Traffic

Data traffic analysis is another detection method that looks at data processed by and transferred to or from a device, inspecting elements like timestamps and data volumes for anomalies.

If the algorithm detects unusual data patterns that indicate a possible ransomware attack, the file system is locked down. The advantage of this approach over signature-based solutions is that it is highly effective at stopping ransomware attacks, and can detect modified ransomware attacks without knowing their malware signature.

The main disadvantage of this approach is the high rate of false positives. In many cases, protective software can block legitimate files or data operations, resulting in costly downtime and hurting productivity.

Detection by Data Behavior

Data behavior monitoring is a technique that monitors file execution to identify anomalies. Behavior-based solutions monitor the behavior of files and processes in the operating system for malicious activity such as encryption or overwriting of DLL files.

Unlike the signature-based and data traffic-based methods, this method does not require a signature and has a lower rate of false positives. Also, it does not need to lock down the entire file system – instead, it can block individual processes that exhibit suspicious behavior.

The downside of this approach is that it can take the system time to analyze process behavior before it can detect ransomware activity. This means that in many cases, some data will be encrypted before the algorithm responds.

Ransomware Protection with Cynet 360

A dedicated security tool can provide holistic protection against ransomware, both at the network, file system, and application layer. One such solution is Cynet 360, an advanced threat detection and response platform that provides protection against threats, including ransomware, zero-day attacks, advanced persistent threats (APT), and trojans that can evade signature-based security measures.

Cynet provides a multi-layered approach to stop ransomware from executing and encrypting your data:

• Pre-download—applies multiple mechanisms against exploits and fileless malware, which typically serves as a delivery method for the ransomware payload, preventing it from getting to the endpoint in the first place.
• Pre-execution prevention—applies machine-learning-based static analysis to identify ransomware patterns in binary files before they are executed.
• In runtime—employs behavioral analysis to identify ransomware-like behavior, and kill a process if it exhibits such behavior.
• Threat intelligence—uses a live feed comprising over 30 threat intelligence feeds to identify known ransomware.
• Fuzzy detection—employs a fuzzy hashing detection mechanism to detect automated variants of known ransomware.
• Sandbox—runs any loaded file in a sandbox and blocks execution upon identification of ransomware-like behavior.
• Decoy files—plants decoy data files on the hosts and applies a mechanism to ensure these are the first to be encrypted in a case of ransomware. Once Cynet detects that these files are going through encryption it kills the ransomware process.
• Propagation blocking—identifies the networking activity signature generated by hosts when ransomware is auto-propagating, and isolates the hosts from the network.

Learn more about how Cynet 360 can protect your organization against ransomware and other advanced threats.