YARA — CySA+ Tools — Thiago Teixeira

YARA

VirusTotal / Community

Pattern-matching engine for classifying and identifying malware samples.

Malware Analysis & Sandboxing Free & Open Source CLI Learning Cross-platform

Cyber Kill Chain & Defender Lifecycle

Attacker — Kill Chain

1 Reconnaissance

2 Weaponization

3 Delivery

4 Exploitation

5 Installation

6 Command & Control

7 Actions on Objectives

Defender — IR Lifecycle

8 Detection / Monitoring

9 Containment & Eradication

10 Post-incident Forensics

Description

YARA ("Yet Another Recursive Acronym") is the de facto standard for writing signatures that describe families of malware. A YARA rule combines text/byte strings, regex, and a Boolean condition that fires when the sample matches.

Analysts use YARA in three main contexts:

Triage of large file sets (a SOC pipeline scans every email attachment with hundreds of rules).
Threat hunting in memory captures (Volatility's yarascan plugin, loki, THOR).
IOC sharing — vendors and CERTs publish YARA rules alongside CVE / IOC reports.

Use cases

Triaging incoming files at the email gateway
Hunting for known malware families across a fleet
Validating sandbox verdicts with offline rules

Example

rule SuspiciousMimikatz {
    meta:
        author = "soc-team"
        description = "Heuristic for Mimikatz-like strings"
    strings:
        $s1 = "sekurlsa::logonpasswords" ascii wide
        $s2 = "privilege::debug" ascii wide
    condition:
        any of them
}