dionysos

Scanner for various IoCs

Installation

shell sudo apt install libyara-dev cargo install dionysos

Features

| Feature | Details | |-|-| |Scanners | filenames (by regular expressions), similar filenames (Levenshtein), yara, hashes| | Output formats | human-readable text (txt), comma-separated values (csv, conforming to RFC4180), JavaScript Object Notation (json), can be selected with --format <txt\|csv\|json> | | Scan of compressed files | yara-scan of zip, xz, gz and bz2 compressed files is supported; see -C switch. Be aware that files are decompressed into a decompression buffer, and that every thread gets its own decompression buffer. You should make sure that you have sufficient memory. If you need larger buffers, you can limit the number of threads using --threads | | Special features | yara-scan in Windows evtx files and Windows registry hives using --evtx and --reg|

Usage

``` dionysos 1.0.0 Jan Starke Jan.Starke@t-systems.com Scanner for various IoCs

USAGE: dionysos [OPTIONS]

OPTIONS: -P, --path path which must be scanned

-f, --format <OUTPUT_FORMAT>
        output format [default: txt] [possible values: csv, txt, json]

-Y, --yara <YARA>
        use yara scanner with the specified ruleset. This can be a single file, a zip file or a
        directory containing lots of yara files. Yara files must end with 'yar' or 'yara', and
        zip files must end with 'zip'

    --yara-timeout <YARA_TIMEOUT>
        timeout for the yara scanner, in seconds [default: 240]

-s, --print-strings
        print matching strings (only used by yara currently)

    --evtx
        also do YARA scan in Windows EVTX records (exported as JSON)

    --reg
        also do YARA scan in Windows registry hive files

-C, --scan-compressed
        allow yara to scan compressed files. Currently, xz, bz2 and gz are supported

    --decompression-buffer <DECOMPRESSION_BUFFER_SIZE>
        maximum size (in MiB) of decompression buffer (per thread), which is used to scan
        compressed files [default: 128]

-H, --file-hash <FILE_HASH>
        Hash of file to match against. Use any of MD5, SHA1 or SHA256. This parameter can be
        specified multiple times

-F, --filename <FILENAMES>
        regular expression to match against the basename of files. This parameter can be
        specified multiple times

    --levenshtein
        run the Levenshtein scanner

-p, --threads <THREADS>
        use the specified NUMBER of threads [default: 16]

    --progress
        display a progress bar (requires counting the number of files to be scanned before a
        progress bar can be displayed)

-L, --log-file <LOG_FILE>
        path of the file to write logs to. Logs will always be appended

-h, --help
        Print help information

-q, --quiet
        Less output per occurrence

-v, --verbose
        More output per occurrence

-V, --version
        Print version information

```

Developer guide

How to add scanners

1. Implement a special result type for the scanner

For example, say we want to scan for files whose name match a regular expression. Our finding type could look like this:

rust struct FilenameFinding { filename: String, pattern: regex::Regex, }

Every finding type needs to implement Display and ScannerFinding:

```rust impl ScannerFinding for FilenameFinding {

fn format_readable(&self, file: &str, _show_details: bool) -> Vec<String> {
    vec![
        format!("the name of '{}' matches the pattern /{}/", file, self.pattern)
    ]
}

fn format_csv<'a, 'b>(&'b self, file: &'a str) -> HashSet<crate::scanner_result::CsvLine> {
    hashset![CsvLine::new("Filename", &self.filename, file, String::new())]
}

fn to_json(&self, file: &str) -> serde_json::Value {
    json!({
        "01_scanner": "filename",
        "02_suspicious_file": file,
        "03_pattern": format!("{}", self.pattern)
    })
}

} ```

2. Implementation of the scanner

Take, for example, the FilenameScanner, which tries to do a simple filename match:

```rust pub struct FilenameScanner { patterns: Vec, }

impl FilenameScanner { pub fn new(patterns: Vec) -> Self { Self {
patterns, } } }

impl Display for FilenameScanner { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "{}", "FilenameScanner") } }

impl FileScanner for FilenameScanner { fn scanfile(&self, file: &DirEntry) -> Vec>> { let file = file.path(); let filename = file.tostr().unwrap(); let mut results = Vec::new(); for pattern in self.patterns.iter() { if pattern.ismatch(&filename) { results.push( Ok( Box::new( FilenameFinding{ filename: filename.toowned(), pattern: pattern.clone() } ) as Box ) ) } } results } } ```

3. Add your scanner to the scanner chain

Which is currently hard-coded in Dionysos::run() (in src/dionysos.rs)