Cole Munz
8a5a88e463
args_parse zeroed every option's value pointer right before returning, so args_free's NULL check always skipped the free. Even without that, args_free was freeing the address of the caller's static variable (e.g. &ext_vars), not the string it points to. On Windows (_UNICODE builds) each ARGS_OPT_STRING value is a heap copy from unicode_to_ansi(), so -d, -x, -i, atom-quality-table and module-data args leaked on every run. On non-Windows the value just aliases argv, nothing to free. Removed the value-clearing loop in args_parse (nothing reads .value after parsing except args_free) and rewrote args_free to walk options->count entries and free the actual string pointers, gated on _UNICODE so it's a no-op elsewhere.
Important
This project is in maintenance mode. More info: https://virustotal.github.io/yara-x/blog/yara-x-is-stable/
YARA in a nutshell
YARA is a tool aimed at (but not limited to) helping malware researchers to identify and classify malware samples. With YARA you can create descriptions of malware families (or whatever you want to describe) based on textual or binary patterns. Each description, a.k.a. rule, consists of a set of strings and a boolean expression which determine its logic. Let's see an example:
rule silent_banker : banker
{
meta:
description = "This is just an example"
threat_level = 3
in_the_wild = true
strings:
$a = {6A 40 68 00 30 00 00 6A 14 8D 91}
$b = {8D 4D B0 2B C1 83 C0 27 99 6A 4E 59 F7 F9}
$c = "UVODFRYSIHLNWPEJXQZAKCBGMT"
condition:
$a or $b or $c
}
The above rule is telling YARA that any file containing one of the three strings must be reported as silent_banker. This is just a simple example, more complex and powerful rules can be created by using wild-cards, case-insensitive strings, regular expressions, special operators and many other features that you'll find explained in YARA's documentation.
YARA is multi-platform, running on Windows, Linux and Mac OS X, and can be used through its command-line interface or from your own Python scripts with the yara-python extension.
Additional resources
Do you use GitHub for storing your YARA rules? YARA-CI may be a useful addition to your toolbelt. This is GitHub application that provides continuous testing for your rules, helping you to identify common mistakes and false positives.
If you plan to use YARA to scan compressed files (.zip, .tar, etc) you should take a look at yextend, a very helpful extension to YARA developed and open-sourced by Bayshore Networks.
Additionally, the guys from InQuest have curated an awesome list of YARA-related stuff.
Who's using YARA
- 0x101 Cyber Security
- Adlice
- AlienVault
- Avast
- BAE Systems
- Bayshore Networks, Inc.
- Binalyze
- BinaryAlert
- Blueliv
- Cado Security
- Cisco Talos Intelligence Group
- Cloudina Security
- Cofense
- Conix
- Corelight
- CounterCraft
- Cuckoo Sandbox
- Cyber Triage
- Cybereason
- Digita Security
- Dragos Platform
- Dtex Systems
- ESET
- ESTsecurity
- Elastic Security
- FactorX.ai
- Fidelis XPS
- FireEye, Inc.
- Forcepoint
- Fox-IT
- FSF
- Guidance Software
- Heroku
- Hornetsecurity
- ICS Defense
- InQuest
- IntelOwl
- Joe Security
- Kaspersky Lab
- KnowBe4
- Koodous
- Laika BOSS
- Lastline, Inc.
- libguestfs
- LimaCharlie
- Malpedia
- Malwation
- McAfee Advanced Threat Defense
- Metaflows
- NBS System
- ndaal
- NetLock
- Nextron Systems
- Nozomi Networks
- osquery
- Payload Security
- PhishMe
- Picus Security
- Radare2
- RedSocks Security
- ReversingLabs
- Scanii
- SecondWrite
- SonicWall
- SpamStopsHere
- Spyre
- stoQ
- Sublime Security
- SumoLogic
- Tanium
- Tenable Network Security
- Tenzir
- The DigiTrust Group
- ThreatConnect
- ThreatStream, Inc.
- Thug
- Threat.Zone
- TouchWeb
- Trend Micro
- UnpacMe
- UpSight Security Inc.
- Uptycs Inc
- Veeam
- Verisys Antivirus API
- VirusTotal Intelligence
- VMRay
- Volexity
- We Watch Your Website
- x64dbg
- YALIH
Are you using it? Want to see your site listed here?