https://github.com/neo23x0/yaraqa
YARA rule analyzer to improve rule quality and performance
https://github.com/neo23x0/yaraqa
detection malware-detection malware-research signatures yara
Last synced: 7 months ago
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YARA rule analyzer to improve rule quality and performance
- Host: GitHub
- URL: https://github.com/neo23x0/yaraqa
- Owner: Neo23x0
- License: gpl-3.0
- Created: 2023-01-03T10:08:49.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2024-12-23T08:46:38.000Z (10 months ago)
- Last Synced: 2025-04-04T14:40:23.776Z (7 months ago)
- Topics: detection, malware-detection, malware-research, signatures, yara
- Language: Python
- Homepage:
- Size: 8.15 MB
- Stars: 98
- Watchers: 6
- Forks: 6
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# yaraQA
YARA rule Analyzer to improve rule quality and performance
## Why?
YARA rules can be syntactically correct but still dysfunctional. yaraQA tries to find and report these issues to the author or maintainer of a YARA rule set.
The issues yaraQA tries to detect are e.g.:
- rules that are syntactically correct but never match due to errors in the condition (e.g. rule with one string and `2 of them` in the condition)
- rules that use string and modifier combinations that are probably wrong (e.g. `$ = "\\Debug\\" fullword`)
- performance issues caused by short atoms, repeating characters or loops (e.g. `$ = "AA"`; can be excluded from the analysis using `--ignore-performance`)
I'm going to extend the test set over time. Each minor version will include new features or new tests.
## Install requirements
```bash
pip install -r requirements.txt
```
## Usage
```bash
usage: yaraQA.py [-h] [-f yara files [yara files ...]] [-d yara files [yara files ...]] [-o outfile] [-b baseline] [-l level]
[--ignore-performance] [--debug]
YARA RULE ANALYZER
optional arguments:
-h, --help show this help message and exit
-f yara files [yara files ...]
Path to input files (one or more YARA rules, separated by space)
-d yara files [yara files ...]
Path to input directory (YARA rules folders, separated by space)
-o outfile Output file that lists the issues (JSON, default: 'yaraQA-issues.json')
-b baseline Use a issues baseline (issues found and reviewed before) to filter issues
-l level Minium level to show (1=informational, 2=warning, 3=critical)
--ignore-performance Suppress performance-related rule issues
--debug Debug output
```
## Try it out
```bash
python3 yaraQA.py -d ./test/
```
Suppress all performance issues and only show detection / logic issues.
```bash
python3 yaraQA.py -d ./test/ --ignore-performance
```
Suppress all issues of informational character
```bash
python3 yaraQA.py -d ./test/ -level 2
```
Use a baseline to only see new issues (not the ones that you've already reviewed). The baseline file is an old JSON output of a reviewed state.
```bash
python3 yaraQA.py -d ./test/ -b yaraQA-reviewed-issues.json
```
## Example Rules with Issues
Example rules with issues can be found in the `./test` folder.
## Output
yaraQA writes the detected issues to a file named `yaraQA-issues.json` by default.
This listing shows an example of the output generated by yaraQA in JSON format:
```json
[
{
"rule": "Demo_Rule_1_Fullword_PDB",
"id": "SM1",
"issue": "The rule uses a PDB string with the modifier 'wide'. PDB strings are always included as ASCII strings. The 'wide' keyword is unneeded.",
"element": {
"name": "$s1",
"value": "\\\\i386\\\\mimidrv.pdb",
"type": "text",
"modifiers": [
"ascii",
"wide",
"fullword"
]
},
"level": "info",
"type": "logic",
"recommendation": "Remove the 'wide' modifier"
},
{
"rule": "Demo_Rule_1_Fullword_PDB",
"id": "SM2",
"issue": "The rule uses a PDB string with the modifier 'fullword' but it starts with two backslashes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": "$s1",
"value": "\\\\i386\\\\mimidrv.pdb",
"type": "text",
"modifiers": [
"ascii",
"wide",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
},
{
"rule": "Demo_Rule_2_Short_Atom",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",
"element": {
"name": "$s1",
"value": "{ 01 02 03 }",
"type": "byte"
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_3_Fullword_FilePath_Section",
"id": "SM3",
"issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backslashes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": "$s1",
"value": "\\\\ZombieBoy\\\\",
"type": "text",
"modifiers": [
"ascii",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
},
{
"rule": "Demo_Rule_4_Condition_Never_Matches",
"id": "CE1",
"issue": "The rule uses a condition that will never match",
"element": {
"condition_segment": "2 of",
"num_of_strings": 1
},
"level": "error",
"type": "logic",
"recommendation": "Fix the condition"
},
{
"rule": "Demo_Rule_5_Condition_Short_String_At_Pos",
"id": "PA1",
"issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.",
"element": {
"condition_segment": "$mz at 0",
"string": "$mz",
"value": "MZ"
},
"level": "warning",
"type": "performance",
"recommendation": ""
},
{
"rule": "Demo_Rule_5_Condition_Short_String_At_Pos",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",
"element": {
"name": "$mz",
"value": "MZ",
"type": "text",
"modifiers": [
"ascii"
]
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "PA1",
"issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.",
"element": {
"condition_segment": "$mz at 0",
"string": "$mz",
"value": "{ 4d 5a }"
},
"level": "warning",
"type": "performance",
"recommendation": ""
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",
"element": {
"name": "$mz",
"value": "{ 4d 5a }",
"type": "byte"
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "SM3",
"issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backslashes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": "$s1",
"value": "\\\\Section\\\\in\\\\Path\\\\",
"type": "text",
"modifiers": [
"ascii",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
}
]
```
## Screenshots
