YARA — Security analysis and diagnosis

A malware detection and classification tool that finds patterns defined by rules in text and binary files.

Basic information

What is this program?

YARA is a rule engine that finds specific strings, byte sequences, and condition combinations in files and memory — like a package. When security researchers define malware characteristics in rules files, it collects the files that match those rules from the scan target.

It is used as a command-line tool (yarac and yara), but at its core it is a rule language. You can combine not only string matches but also logical conditions such as PE header values, XOR obfuscation conditions, and wildcards, so it is also used as a standard in community and commercial detection engines.

What problems does it solve?

• ('In security checks', 'when you need to quickly determine whether a suspicious file is related to malware functionality', 'you can scan with existing public rules to identify similar characteristics.')
• ('In forensics', 'when you need to pick out only attack-related files from large volumes of logs and files', 'you can filter with rules to narrow the analysis target.')
• ('In detection pipelines', 'when automatic classification is needed for file collection and storage', 'you can combine rule scanning with CI and monitoring systems.')

Key features

Rule-based scanning

Define detection rules with strings and condition blocks to scan files.

• When to use: Apply public malware rules
• What you get: A list of matching files and offsets
• Limitations: False positives and false negatives vary greatly depending on rule quality.

Multiple input formats

Scan files, directories, and memory dumps.

• When to use: Forensics and real-time monitoring
• What you get: Process various evidence sources with a single engine
• Limitations: Large traffic requires management of scan costs.

Compilation and reuse

Compile and distribute rules with yarac.

• When to use: Rebuild rules when updating the engine
• What you get: Reduced runtime rule loading costs
• Limitations: Use caution with platform-specific binary compilation.

Module support

Extend conditions with file structure modules such as PE, ELF, and dotnet.

• When to use: Detailed conditions for executable files
• What you get: Precise rules using headers, sections, and import tables
• Limitations: Requires learning the module documentation.

Installation and execution

Linux (source build)

Install build dependencies (automake, libtool, openssl-dev), then build from source.

sudo apt install automake libtool libssl-dev gcc make
git clone https://github.com/VirusTotal/yara.git
cd yara && ./bootstrap.sh && ./configure && make && sudo make install

Linux (distribution package)

Available in some distribution repositories. The version may be outdated.

sudo apt install yara

macOS / Windows

Install with brew or by building from source.

brew install yara   # macOS
# Windows: Cygwin/WSL environment or build from source

Real-world usage examples

Writing a rule file

Define a rule with the rule keyword, write patterns in strings, and write matching conditions in condition.

$ cat susp_http.yar
rule suspicious_http {
  strings:
    $a = "User-Agent: sqlmap"
    $b = "UNION SELECT"
  condition:
    any of them
}

Directory scanning

Specify a rule file and a target directory to yara to check matching results.

$ yara susp_http.yar /var/log/apache2/
suspicious_http /var/log/apache2/access.log
suspicious_http /var/log/apache2/error.log

Compilation and distribution

Compile rules with yarac to load them quickly when scanning.

$ yarac susp_http.yar susp_http.compiled
$ yara -C susp_http.compiled /srv/www/uploads/

Advantages and limitations

Advantages

• Free and open source (GPL) — community-published rules can be used as-is
• The rule language is flexible, enabling precise detection by combining strings, headers, and logical conditions
• Lightweight and low-resource — low burden even for always-on server monitoring
• Broad range of uses, including forensics, detection, and CI pipelines

Points to consider before use

• Detection quality depends heavily on rule-writing skill.
• Simple string rules can be vulnerable to obfuscation.
• Public rules alone may not cover targeted attacks.

Comparison with similar programs

Official resources and further learning

• Official homepage — https://virustotal.com/yara/
• Official documentation / knowledge base — https://yara.readthedocs.io/
• Official download — https://github.com/VirusTotal/yara/releases
• Release notes — https://github.com/VirusTotal/yara/releases
• Source / development resources — https://github.com/VirusTotal/yara

Version and supported environment information was checked on the official site as of 2026-10-18. Installation commands may vary depending on your distribution and version, so check the official installation documentation as well.

Actual execution screen

The screen below is a synthetic example created to help understand the usage flow (not an actual execution result). The screen is a synthetic example and not an actual execution result.

!YARA example: writing a rule file, scanning a directory, and compiling with yarac

Actual production server

Source (HTML): https://games.aidebatehub.com/programs/apps/security/yara.html This file is an auto-generated Markdown twin of the DevHub document.