libsast
Generic SAST for Security Engineers. Powered by regex based pattern matcher and semantic aware semgrep.
Support libsast
Install
pip install libsast
Pattern Matcher is cross-platform, but Semgrep supports only Mac and Linux.
Command Line Options
$ libsast
usage: libsast [-h] [-o OUTPUT] [-p PATTERN_FILE] [-s SGREP_PATTERN_FILE]
[--sgrep-file-extensions SGREP_FILE_EXTENSIONS [SGREP_FILE_EXTENSIONS ...]]
[--file-extensions FILE_EXTENSIONS [FILE_EXTENSIONS ...]]
[--ignore-filenames IGNORE_FILENAMES [IGNORE_FILENAMES ...]]
[--ignore-extensions IGNORE_EXTENSIONS [IGNORE_EXTENSIONS ...]]
[--ignore-paths IGNORE_PATHS [IGNORE_PATHS ...]]
[--show-progress] [-v]
[path [path ...]]
positional arguments:
path Path can be file(s) or directories
optional arguments:
-h, --help show this help message and exit
-o OUTPUT, --output OUTPUT
Output filename to save JSON report.
-p PATTERN_FILE, --pattern-file PATTERN_FILE
YAML pattern file, directory or url
-s SGREP_PATTERN_FILE, --sgrep-pattern-file SGREP_PATTERN_FILE
sgrep rules directory
--sgrep-file-extensions SGREP_FILE_EXTENSIONS [SGREP_FILE_EXTENSIONS ...]
File extensions that should be scanned with sgrep
--file-extensions FILE_EXTENSIONS [FILE_EXTENSIONS ...]
File extensions that should be scanned with pattern
matcher
--ignore-filenames IGNORE_FILENAMES [IGNORE_FILENAMES ...]
File name(s) to ignore
--ignore-extensions IGNORE_EXTENSIONS [IGNORE_EXTENSIONS ...]
File extension(s) to ignore in lower case
--ignore-paths IGNORE_PATHS [IGNORE_PATHS ...]
Path(s) to ignore
--show-progress Show scan progress
-v, --version Show libsast version
Example Usage
$ libsast -s tests/assets/rules/semantic_grep/ -p tests/assets/rules/pattern_matcher/ tests/assets/files/
{
"pattern_matcher": {
"test_regex": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
28,
28
],
"match_position": [
1141,
1149
],
"match_string": ".close()"
}
],
"metadata": {}
},
"test_regex_and": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
3,
3
],
"match_position": [
52,
66
],
"match_string": "webkit.WebView"
},
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
7,
7
],
"match_position": [
194,
254
],
"match_string": ".loadUrl(\"file:/\" + Environment.getExternalStorageDirectory("
}
],
"metadata": {}
},
"test_regex_and_not": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
42,
42
],
"match_position": [
1415,
1424
],
"match_string": "WKWebView"
},
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
40,
40
],
"match_position": [
1363,
1372
],
"match_string": "WKWebView"
}
],
"metadata": {}
},
"test_regex_and_or": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
50,
50
],
"match_position": [
1551,
1571
],
"match_string": "telephony.SmsManager"
},
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
58,
58
],
"match_position": [
1973,
1988
],
"match_string": "sendTextMessage"
}
],
"metadata": {}
},
"test_regex_multiline_and_metadata": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
52,
52
],
"match_position": [
1586,
1684
],
"match_string": "public void onRequestPermissionsResult(int requestCode,String permissions[], int[] grantResults) {"
},
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
10,
11
],
"match_position": [
297,
368
],
"match_string": "public static ForgeAccount add(Context context, ForgeAccount account) {"
}
],
"metadata": {
"cwe": "CWE-1051 Initialization with Hard-Coded Network Resource Configuration Data",
"description": "This is a rule to test regex",
"foo": "bar",
"masvs": "MSTG-STORAGE-3",
"owasp-mobile": "M1: Improper Platform Usage",
"owasp-web": "A10: Insufficient Logging & Monitoring",
"severity": "info"
}
},
"test_regex_or": {
"files": [
{
"file_path": "tests/assets/files/test_matcher.test",
"match_lines": [
26,
26
],
"match_position": [
1040,
1067
],
"match_string": "Context.MODE_WORLD_READABLE"
}
],
"metadata": {}
}
},
"semantic_grep": {
"errors": [
{
"code": 3,
"level": "warn",
"message": "Semgrep Core WARN - Lexical error in file tests/assets/files/test_matcher.test:40\n\tunrecognized symbols: !",
"path": "tests/assets/files/test_matcher.test",
"type": "Lexical error"
},
],
"matches": {
"boto-client-ip": {
"files": [
{
"file_path": "tests/assets/files/example_file.py",
"match_lines": [
4,
4
],
"match_position": [
24,
31
],
"match_string": "c = boto3.client(host='8.8.8.8')"
}
],
"metadata": {
"cwe": "CWE-1050 Excessive Platform Resource Consumption within a Loop",
"description": "boto client using IP address",
"owasp-web": "A8: Insecure Deserialization",
"severity": "ERROR"
}
}
}
}
}
Python API
>>> from libsast import Scanner
>>> options = {'match_rules': '/Users/ajinabraham/Code/njsscan/njsscan/rules/pattern_matcher', 'sgrep_rules': '/Users/ajinabraham/Code/njsscan/njsscan/rules/semantic_grep', 'sgrep_extensions': {'', '.js'}, 'match_extensions': {'.hbs', '.sh', '.ejs', '.toml', '.mustache', '.tmpl', '.jade', '.json', '.ect', '.vue', '.yml', '.hdbs', '.tl', '.html', '.haml', '.dust', '.pug', '.tpl'}, 'ignore_filenames': {'bootstrap.min.js', '.DS_Store', 'bootstrap-tour.js', 'd3.min.js', 'tinymce.js', 'codemirror.js', 'tinymce.min.js', 'react-dom.production.min.js', 'react.js', 'jquery.min.js', 'react.production.min.js', 'codemirror-compressed.js', 'axios.min.js', 'angular.min.js', 'raphael-min.js', 'vue.min.js'}, 'ignore_extensions': {'.7z', '.exe', '.rar', '.zip', '.a', '.o', '.tz'}, 'ignore_paths': {'__MACOSX', 'jquery', 'fixtures', 'node_modules', 'bower_components', 'example', 'spec'}, 'show_progress': False}
>>> paths = ['../njsscan/tests/assets/dot_njsscan/']
>>> scanner = Scanner(options, paths)
>>> scanner.scan()
{'pattern_matcher': {'handlebar_mustache_template': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/ignore_ext.hbs', 'match_string': '{{{html}}}', 'match_position': (52, 62), 'match_lines': (1, 1)}], 'metadata': {'id': 'handlebar_mustache_template', 'description': 'The Handlebar.js/Mustache.js template has an unescaped variable. Untrusted user input passed to this variable results in Cross Site Scripting (XSS).', 'type': 'Regex', 'pattern': '{{{.+}}}|{{[ ]*&[\\w]+.*}}', 'severity': 'ERROR', 'input_case': 'exact', 'cwe': "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", 'owasp': 'A1: Injection'}}}, 'semantic_grep': {'matches': {'node_aes_ecb': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/lorem_scan.js', 'match_position': (16, 87), 'match_lines': (14, 14), 'match_string': "let decipher = crypto.createDecipheriv('aes-128-ecb', Buffer.from(ENCRYPTION_KEY), iv);"}], 'metadata': {'owasp': 'A9: Using Components with Known Vulnerabilities', 'cwe': 'CWE-327: Use of a Broken or Risky Cryptographic Algorithm', 'description': 'AES with ECB mode is deterministic in nature and not suitable for encrypting large amount of repetitive data.', 'severity': 'ERROR'}}, 'node_tls_reject': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/skip_dir/skip_me.js', 'match_position': (9, 58), 'match_lines': (9, 9), 'match_string': " process.env['NODE_TLS_REJECT_UNAUTHORIZED'] = '0';"}, {'file_path': '../njsscan/tests/assets/dot_njsscan/skip_dir/skip_me.js', 'match_position': (9, 55), 'match_lines': (18, 18), 'match_string': ' process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";'}], 'metadata': {'owasp': 'A6: Security Misconfiguration', 'cwe': 'CWE-295: Improper Certificate Validation', 'description': "Setting 'NODE_TLS_REJECT_UNAUTHORIZED' to 0 will allow node server to accept self signed certificates and is not a secure behaviour.", 'severity': 'ERROR'}}, 'node_curl_ssl_verify_disable': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/skip_dir/skip_me.js', 'match_position': (5, 11), 'match_lines': (45, 51), 'match_string': ' curl(url,\n\n {\n\n SSL_VERIFYPEER: 0\n\n },\n\n function (err) {\n\n response.end(this.body);\n\n })'}], 'metadata': {'owasp': 'A6: Security Misconfiguration', 'cwe': 'CWE-599: Missing Validation of OpenSSL Certificate', 'description': 'SSL Certificate verification for node-curl is disabled.', 'severity': 'ERROR'}}, 'regex_injection_dos': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/lorem_scan.js', 'match_position': (5, 37), 'match_lines': (25, 27), 'match_string': ' var key = req.param("key");\n\n // Regex created from user input\n\n var re = new RegExp("\\\\b" + key);'}], 'metadata': {'owasp': 'A1: Injection', 'cwe': 'CWE-400: Uncontrolled Resource Consumption', 'description': 'User controlled data in RegExp() can make the application vulnerable to layer 7 DoS.', 'severity': 'ERROR'}}, 'express_xss': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/skip.js', 'match_position': (9, 55), 'match_lines': (7, 10), 'match_string': ' var str = new Buffer(req.cookies.profile, \'base64\').toString();\n\n var obj = serialize.unserialize(str);\n\n if (obj.username) {\n\n res.send("Hello " + escape(obj.username));'}], 'metadata': {'owasp': 'A1: Injection', 'cwe': "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", 'description': 'Untrusted User Input in Response will result in Reflected Cross Site Scripting Vulnerability.', 'severity': 'ERROR'}}, 'generic_path_traversal': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/lorem_scan.js', 'match_position': (5, 35), 'match_lines': (36, 37), 'match_string': " var filePath = path.join(__dirname, '/' + req.query.load);\n\n fileSystem.readFile(filePath); // ignore: generic_path_traversal"}, {'file_path': '../njsscan/tests/assets/dot_njsscan/lorem_scan.js', 'match_position': (5, 35), 'match_lines': (42, 43), 'match_string': " var filePath = path.join(__dirname, '/' + req.query.load);\n\n fileSystem.readFile(filePath); // detect this"}], 'metadata': {'owasp': 'A5: Broken Access Control', 'cwe': 'CWE-23: Relative Path Traversal', 'description': 'Untrusted user input in readFile()/readFileSync() can endup in Directory Traversal Attacks.', 'severity': 'ERROR'}}, 'express_open_redirect': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/lorem_scan.js', 'match_position': (5, 26), 'match_lines': (49, 51), 'match_string': ' var target = req.param("target");\n\n // BAD: sanitization doesn\'t apply here\n\n res.redirect(target); //ignore: express_open_redirect'}], 'metadata': {'owasp': 'A1: Injection', 'cwe': "CWE-601: URL Redirection to Untrusted Site ('Open Redirect')", 'description': 'Untrusted user input in redirect() can result in Open Redirect vulnerability.', 'severity': 'ERROR'}}, 'node_deserialize': {'files': [{'file_path': '../njsscan/tests/assets/dot_njsscan/skip.js', 'match_position': (19, 45), 'match_lines': (8, 8), 'match_string': ' var obj = serialize.unserialize(str);'}], 'metadata': {'owasp': 'A8: Insecure Deserialization', 'cwe': 'CWE-502: Deserialization of Untrusted Data', 'description': "User controlled data in 'unserialize()' or 'deserialize()' function can result in Object Injection or Remote Code Injection.", 'severity': 'ERROR'}}}, 'errors': [{'type': 'SourceParseError', 'code': 3, 'short_msg': 'parse error', 'long_msg': 'Could not parse .njsscan as javascript', 'level': 'warn', 'spans': [{'start': {'line': 2, 'col': 20}, 'end': {'line': 2, 'col': 21}, 'source_hash': 'c60298be568bfb1325d92cbb3c0bc1450a25b85bb2e4000bdc3267c05f1c8c73', 'file': '.njsscan', 'context_start': None, 'context_end': None}], 'help': 'If the code appears to be valid, this may be a semgrep bug.'}, {'type': 'SourceParseError', 'code': 3, 'short_msg': 'parse error', 'long_msg': 'Could not parse no_ext_scan as javascript', 'level': 'warn', 'spans': [{'start': {'line': 1, 'col': 3}, 'end': {'line': 1, 'col': 5}, 'source_hash': 'f002e2a715be216987dd1b134e7b9fa6eef28e3caa82dead0109c4cdc489e089', 'file': 'no_ext_scan', 'context_start': None, 'context_end': None}], 'help': 'If the code appears to be valid, this may be a semgrep bug.'}]}}
Write you own Static Analysis tool
With libsast, you can write your own static analysis tools. libsast provides two matching engines:
- Pattern Matcher
- Semantic Grep
Pattern Matcher
Currently Pattern Matcher supports any language.
Use Regex 101 to write simple Python Regex rule patterns.
A sample rule looks like
- id: test_regex_or
message: This is a rule to test regex_or
input_case: exact
pattern:
- MODE_WORLD_READABLE|Context\.MODE_WORLD_READABLE
- openFileOutput\(\s*".+"\s*,\s*1\s*\)
severity: error
type: RegexOr
metadata:
owasp-web: a1
reference: http://foo.bar
foo: Some extra metadata
A rule consist of
id
: A unique id for the rule.message
: A description for the rule.input_case
: It can beexact
,upper
orlower
. Data will be converted to lower case/upper case/as it is before comparing with the regex.pattern
: List of patterns depends ontype
.severity
: It can beerror
,warning
orinfo
.type
: Pattern Matcher supportsRegex
,RegexAnd
,RegexOr
,RegexAndOr
,RegexAndNot
.metadata
(optional): Define your own custom fields that you can use as metadata along with standard mappings.
1. Regex - if regex1 in input
2. RegexAnd - if regex1 in input and regex2 in input
3. RegexOr - if regex1 in input or regex2 in input
4. RegexAndOr - if regex1 in input and (regex2 in input or regex3 in input)
5. RegexAndNot - if regex1 in input and not regex2 in input
Example: Pattern Matcher Rule
Test your pattern matcher rules
$ libsast -p tests/assets/rules/pattern_matcher/patterns.yaml tests/assets/files/
Inbuilt Standard Mapping Support
Metadata fields also support libsast standard mapping.
For example, the metadata field owasp-web: a1
will get expanded at runtime as owasp-web: 'A1: Injection'
.
Currently Supports
Semantic Grep
Semantic Grep uses semgrep, a fast and syntax-aware semantic code pattern search for many languages: like grep but for code.
Currently it supports Python, Java, JavaScript, Go and C.
Use semgrep.dev to write semantic grep rule patterns.
A sample rule for Python code looks like
rules:
- id: boto-client-ip
patterns:
- pattern-inside: boto3.client(host="...")
- pattern-regex: '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
message: "boto client using IP address"
languages: [python]
severity: ERROR
metadata:
owasp-web: a2
owasp-mobile: m7
cwe: cwe-1048
foo: Some extra metadata
See semgrep documentation here.
Example: Semantic Grep Rule
Test your semgrep rules
$ libsast -s tests/assets/rules/semantic_grep/sgrep.yaml tests/assets/files/
Realworld Implementations
- njsscan SAST is built with libsast pattern matcher and semantic grep.
- nodejsscan nodejsscan is a static security code scanner for Node.js applications.
- MobSF Static Code Analyzer for Android and iOS mobile applications.
- mobsfscan mobsfscan is a static security code scanner for Mobile applications built for Android (Java, Kotlin) & iOS (Swift, Objective C).