Repository Analysis

VirusTotal/yara

The pattern matching swiss knife

3.4 Likely human-written View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of VirusTotal/yara, a C project with 9,752 GitHub stars. SynthScan v2.0 examined 93,538 lines of code across 179 source files, recording 316 pattern matches distributed across 3 syntactic categories. The overall adjusted score of 3.4 places this repository in the Likely human-written band.

The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).

3.4
Adjusted Score
3.4
Raw Score
100%
Time Factor
2026-07-14
Last Push
9.8K
Stars
C
Language
93.5K
Lines of Code
179
Files
316
Pattern Hits
2026-07-14
Scan Date
0.00
HC Hit Rate

What These Metrics Mean

Adjusted Score
Primary synthetic code indicator. Raw score normalised per 1,000 lines of code and multiplied by the temporal discount factor. This is the definitive comparative metric — use it to rank repositories by AI authorship density.
Raw Score
The unmodified sum of all severity-weighted, context-multiplied pattern match scores before temporal discounting. Reflects the absolute signal strength independent of when the repository was last active.
Time Factor
The temporal discount multiplier (0–100%) applied to the raw score. Repositories last updated before ChatGPT's launch (Nov 2022) receive a 5% factor. Full signal is only assigned to repositories active in the post-adoption era (Jan 2024+).
Pattern Hits
Total count of individual pattern matches across all files and categories. A high hit count with a low score may indicate a very large codebase with isolated AI snippets; a low count with a high score indicates dense, concentrated AI signatures.
HC Hit Rate
High+Critical pattern hits per file, averaged across the repository. This orthogonal signal catches repositories where a few files are densely packed with high-severity AI tells — a strong indicator even when the normalised score appears moderate due to codebase size.
Lines of Code / Files
Total lines and files analysed. The scanner examines 94 file extensions. These denominators are used to normalise the score, enabling fair comparison between repositories of vastly different sizes.

Score History

This chart maps the temporal evolution of the adjusted synthetic code score across successive scan runs. An upward trajectory indicates ongoing incorporation of AI-generated code or expanding LLM-assisted scaffolding; a stable or declining trajectory may reflect active human refactoring, code removal, or the adoption of stricter authorship policies. The dashed secondary line (right axis) independently tracks total raw pattern hit count, which can diverge from the normalised score when codebase size changes significantly between scans.

Severity Breakdown

Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.

CRITICAL 0HIGH 0MEDIUM 1LOW 315

Directory Score Breakdown

This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.

Pattern Findings

The scanner identified 316 distinct pattern matches across 3 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.

Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.

Over-Commented Block313 hits · 313 pts
SeverityFileLineSnippetContext
LOW.readthedocs.yaml21 # builder: "dirhtml"COMMENT
LOWtests/test-rules.c3941 case 2:COMMENT
LOWdocs/conf.py1# -*- coding: utf-8 -*-COMMENT
LOWdocs/conf.py21#sys.path.insert(0, os.path.abspath('.'))COMMENT
LOWdocs/conf.py41COMMENT
LOWdocs/conf.py61COMMENT
LOWdocs/conf.py121# "<project> v<release> documentation".COMMENT
LOWdocs/conf.py141# Add any extra paths that contain custom files (such as robots.txt orCOMMENT
LOWdocs/conf.py161# If false, no module index is generated.COMMENT
LOWdocs/conf.py181# base URL from which the finished HTML is served.COMMENT
LOWdocs/conf.py201#'preamble': '',COMMENT
LOWdocs/conf.py261#texinfo_domain_indices = TrueCOMMENT
LOWcli/unicode.h41#define _T(x) xCOMMENT
LOWcli/unicode.h61#define _tfopen fopenCOMMENT
LOWcli/yara.c41#elseCOMMENT
LOWcli/yara.c61#include "threading.h"COMMENT
LOWlibyara/filemap.c41#include <yara/filemap.h>COMMENT
LOWlibyara/filemap.c61////////////////////////////////////////////////////////////////////////////////COMMENT
LOWlibyara/filemap.c161#include <sys/vfs.h>COMMENT
LOWlibyara/filemap.c261////////////////////////////////////////////////////////////////////////////////COMMENT
LOWlibyara/scanner.c21DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FORCOMMENT
LOWlibyara/object.c21DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FORCOMMENT
LOWlibyara/exec.c21DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FORCOMMENT
LOWlibyara/exec.c41#include <yara/mem.h>COMMENT
LOWlibyara/exec.c101#define check_object_canary(o) \COMMENT
LOWlibyara/atoms.c81#include <string.h>COMMENT
LOWlibyara/atoms.c121 // X? and ?X contribute 4 points. An additional boost consisting in 2x theCOMMENT
LOWlibyara/atoms.c201 return YR_MAX_ATOM_QUALITY - 22 * YR_MAX_ATOM_LENGTH + quality;COMMENT
LOWlibyara/atoms.c241// Returns a numeric value indicating the quality of an atom. The quality isCOMMENT
LOWlibyara/atoms.c441 item->next = list2;COMMENT
LOWlibyara/atoms.c621 *atoms_quality = min_quality;COMMENT
LOWlibyara/atoms.c681}COMMENT
LOWlibyara/atoms.c1181}COMMENT
LOWlibyara/grammar.c61#define YYPUSH 0COMMENT
LOWlibyara/grammar.c81#include <string.h>COMMENT
LOWlibyara/grammar.c101#endifCOMMENT
LOWlibyara/grammar.c201COMMENT
LOWlibyara/grammar.c221# elseCOMMENT
LOWlibyara/grammar.c321#define _META_ 263COMMENT
LOWlibyara/grammar.c341#define _NOCASE_ 283COMMENT
LOWlibyara/grammar.c361#define _IMPORT_ 303COMMENT
LOWlibyara/grammar.c601 (aka HP-UX 11i v2) only through the end of 2022; see Table 2 ofCOMMENT
LOWlibyara/grammar.c621#if defined __UINT_LEAST16_MAX__ && __UINT_LEAST16_MAX__ <= __INT_MAX__COMMENT
LOWlibyara/grammar.c641# define YYPTRDIFF_MAXIMUM PTRDIFF_MAXCOMMENT
LOWlibyara/grammar.c681# endifCOMMENT
LOWlibyara/grammar.c701# define YY_ATTRIBUTE_UNUSEDCOMMENT
LOWlibyara/grammar.c721 _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"") \COMMENT
LOWlibyara/grammar.c741# define YY_IGNORE_USELESS_CAST_END \COMMENT
LOWlibyara/grammar.c761# include <alloca.h> /* INFRINGES ON USER NAME SPACE */COMMENT
LOWlibyara/grammar.c781 /* Pacify GCC's 'empty if-body' warning. */COMMENT
LOWlibyara/grammar.c801# define EXIT_SUCCESS 0COMMENT
LOWlibyara/rules.c21DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FORCOMMENT
LOWlibyara/hex_grammar.h61 _NUMBER_ = 262 /* _NUMBER_ */COMMENT
LOWlibyara/re_lexer.c1#line 1 "libyara/re_lexer.c"COMMENT
LOWlibyara/re_lexer.c21#endifCOMMENT
LOWlibyara/re_lexer.c41#ifdef yy_scan_bytesCOMMENT
LOWlibyara/re_lexer.c61#elseCOMMENT
LOWlibyara/re_lexer.c81#endifCOMMENT
LOWlibyara/re_lexer.c101#ifdef yylex_initCOMMENT
LOWlibyara/re_lexer.c121#elseCOMMENT
253 more matches not shown…
Self-Referential Comments1 hit · 3 pts
SeverityFileLineSnippetContext
MEDIUMdocs/conf.py6# This file is execfile()d with the current directory set to itsCOMMENT
Unused Imports2 hits · 2 pts
SeverityFileLineSnippetContext
LOWdocs/conf.py15CODE
LOWdocs/conf.py16CODE