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Merge pull request #284 from dilanbhalla/gocrypto
Adding Crypto Query/Library
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‎ql/src/experimental/CWE-327/CryptoLibraries.qll

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/**
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* Provides classes for modeling cryptographic libraries.
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*/
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import go
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/**
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* Names of cryptographic algorithms, separated into strong and weak variants.
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*
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* The names are normalized: upper-case, no spaces, dashes or underscores.
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*
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* The names are inspired by the names used in real world crypto libraries.
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*
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* The classification into strong and weak are based on OWASP and Wikipedia (2020).
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*
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* Sources (more links in qhelp file):
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* https://en.wikipedia.org/wiki/Strong_cryptography#Cryptographically_strong_algorithms
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* https://en.wikipedia.org/wiki/Strong_cryptography#Examples
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* https://cheatsheetseries.owasp.org/cheatsheets/Cryptographic_Storage_Cheat_Sheet.html
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*/
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private module AlgorithmNames {
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predicate isStrongHashingAlgorithm(string name) {
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name = "DSA" or
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name = "ED25519" or
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name = "ES256" or
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name = "ECDSA256" or
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name = "ES384" or
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name = "ECDSA384" or
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name = "ES512" or
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name = "ECDSA512" or
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name = "SHA2" or
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name = "SHA224" or
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name = "SHA256" or
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name = "SHA384" or
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name = "SHA512" or
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name = "SHA3"
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}
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predicate isWeakHashingAlgorithm(string name) {
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name = "HAVEL128" or
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name = "MD2" or
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name = "MD4" or
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name = "MD5" or
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name = "PANAMA" or
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name = "RIPEMD" or
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name = "RIPEMD128" or
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name = "RIPEMD256" or
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name = "RIPEMD320" or
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name = "SHA0" or
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name = "SHA1"
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}
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predicate isStrongEncryptionAlgorithm(string name) {
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name = "AES" or
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name = "AES128" or
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name = "AES192" or
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name = "AES256" or
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name = "AES512" or
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name = "RSA" or
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name = "RABBIT" or
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name = "BLOWFISH"
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}
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predicate isWeakEncryptionAlgorithm(string name) {
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name = "DES" or
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name = "3DES" or
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name = "TRIPLEDES" or
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name = "TDEA" or
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name = "TRIPLEDEA" or
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name = "ARC2" or
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name = "RC2" or
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name = "ARC4" or
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name = "RC4" or
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name = "ARCFOUR" or
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name = "ARC5" or
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name = "RC5"
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}
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predicate isStrongPasswordHashingAlgorithm(string name) {
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name = "ARGON2" or
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name = "PBKDF2" or
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name = "BCRYPT" or
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name = "SCRYPT"
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}
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predicate isWeakPasswordHashingAlgorithm(string name) { none() }
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}
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private import AlgorithmNames
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/**
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* A cryptographic algorithm.
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*/
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private newtype TCryptographicAlgorithm =
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MkHashingAlgorithm(string name, boolean isWeak) {
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isStrongHashingAlgorithm(name) and isWeak = false
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or
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isWeakHashingAlgorithm(name) and isWeak = true
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} or
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MkEncryptionAlgorithm(string name, boolean isWeak) {
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isStrongEncryptionAlgorithm(name) and isWeak = false
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or
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isWeakEncryptionAlgorithm(name) and isWeak = true
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} or
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MkPasswordHashingAlgorithm(string name, boolean isWeak) {
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isStrongPasswordHashingAlgorithm(name) and isWeak = false
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or
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isWeakPasswordHashingAlgorithm(name) and isWeak = true
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}
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/**
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* A cryptographic algorithm.
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*/
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abstract class CryptographicAlgorithm extends TCryptographicAlgorithm {
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/** Gets a textual representation of this element. */
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string toString() { result = getName() }
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/**
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* Gets the name of this algorithm.
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*/
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abstract string getName();
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/**
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* Holds if the name of this algorithm matches `name` modulo case,
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* white space, dashes and underscores.
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*/
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bindingset[name]
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predicate matchesName(string name) {
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exists(name.regexpReplaceAll("[-_]", "").regexpFind("(?i)\\Q" + getName() + "\\E", _, _))
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}
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/**
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* Holds if this algorithm is weak.
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*/
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abstract predicate isWeak();
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}
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/**
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* A hashing algorithm such as `MD5` or `SHA512`.
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*/
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class HashingAlgorithm extends MkHashingAlgorithm, CryptographicAlgorithm {
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string name;
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boolean isWeak;
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HashingAlgorithm() { this = MkHashingAlgorithm(name, isWeak) }
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override string getName() { result = name }
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override predicate isWeak() { isWeak = true }
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}
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/**
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* An encryption algorithm such as `DES` or `AES512`.
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*/
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class EncryptionAlgorithm extends MkEncryptionAlgorithm, CryptographicAlgorithm {
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string name;
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boolean isWeak;
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EncryptionAlgorithm() { this = MkEncryptionAlgorithm(name, isWeak) }
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override string getName() { result = name }
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override predicate isWeak() { isWeak = true }
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}
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/**
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* A password hashing algorithm such as `PBKDF2` or `SCRYPT`.
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*/
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class PasswordHashingAlgorithm extends MkPasswordHashingAlgorithm, CryptographicAlgorithm {
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string name;
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boolean isWeak;
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PasswordHashingAlgorithm() { this = MkPasswordHashingAlgorithm(name, isWeak) }
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override string getName() { result = name }
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override predicate isWeak() { isWeak = true }
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}
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/**
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* An application of a cryptographic algorithm.
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*/
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abstract class CryptographicOperation extends DataFlow::Node {
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/**
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* Gets the input the algorithm is used on, e.g. the plain text input to be encrypted.
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*/
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abstract Expr getInput();
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/**
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* Gets the applied algorithm.
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*/
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abstract CryptographicAlgorithm getAlgorithm();
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}
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/**
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* Models cryptographic operations of the `crypto/md5` package.
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*/
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class Md5 extends CryptographicOperation, DataFlow::CallNode {
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Md5() { getTarget().hasQualifiedName("crypto/md5", ["New", "Sum"]) }
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override Expr getInput() { result = this.getArgument(0).asExpr() }
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override CryptographicAlgorithm getAlgorithm() {
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result.matchesName(this.getTarget().getPackage().getName())
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}
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}
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/**
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* Models cryptographic operations of the `crypto/sha1` package.
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*/
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class Sha1 extends CryptographicOperation, DataFlow::CallNode {
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Sha1() { getTarget().hasQualifiedName("crypto/sha1", ["New", "Sum"]) }
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override Expr getInput() { result = this.getArgument(0).asExpr() }
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override CryptographicAlgorithm getAlgorithm() {
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result.matchesName(this.getTarget().getPackage().getName())
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}
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}
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/**
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* Models cryptographic operations of the `crypto/des` package.
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*/
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class Des extends CryptographicOperation, DataFlow::CallNode {
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Des() { getTarget().hasQualifiedName("crypto/des", ["NewCipher", "NewTripleDESCipher"]) }
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override Expr getInput() { result = this.getArgument(0).asExpr() }
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override CryptographicAlgorithm getAlgorithm() {
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result.matchesName(this.getTarget().getPackage().getName())
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}
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}
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/**
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* Models cryptographic operations of the `crypto/rc4` package.
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*/
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class Rc4 extends CryptographicOperation, DataFlow::CallNode {
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Rc4() { getTarget().hasQualifiedName("crypto/rc4", ["NewCipher"]) }
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override Expr getInput() { result = this.getArgument(0).asExpr() }
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override CryptographicAlgorithm getAlgorithm() {
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result.matchesName(this.getTarget().getPackage().getName())
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}
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}

‎ql/src/experimental/CWE-327/WeakCryptoAlgorithm.qhelp

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<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>
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Using weak cryptographic algorithms can leave data
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vulnerable to being decrypted or forged by an attacker.
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</p>
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<p>
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Many cryptographic algorithms provided by cryptography
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libraries are known to be weak. Using such an
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algorithm means that encrypted or hashed data is less
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secure than it appears to be.
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</p>
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</overview>
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<recommendation>
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<p>
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Ensure that you use a strong, modern cryptographic
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algorithm. Use at least AES-128 or RSA-2048 for
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encryption, and SHA-2 or SHA-3 for secure hashing.
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</p>
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</recommendation>
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<example>
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<p>
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The following code uses the different packages to encrypt/hash
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some secret data. The first few examples uses DES, MD5, RC4, and SHA1,
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which are older algorithms that are now considered weak. The following
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examples use AES and SHA256, which are stronger, more modern algorithms.
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</p>
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<sample src="examples/Crypto.go" />
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</example>
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<references>
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<li>OWASP: <a
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href="https://cheatsheetseries.owasp.org/cheatsheets/Cryptographic_Storage_Cheat_Sheet.html">Cryptographic Storage Cheat Sheet</a>.
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</li>
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<li>Wikipedia: <a
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href="https://en.wikipedia.org/wiki/Strong_cryptography#Cryptographically_strong_algorithms">Cryptographically Strong Algorithms</a>.
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</li>
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<li>Wikipedia: <a
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href="https://en.wikipedia.org/wiki/Strong_cryptography#Examples">Strong Cryptography Examples</a>.
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</li>
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<li>NIST, FIPS 140 Annex a: <a href="http://csrc.nist.gov/publications/fips/fips140-2/fips1402annexa.pdf"> Approved Security Functions</a>.</li>
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<li>NIST, SP 800-131A: <a href="http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar1.pdf"> Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths</a>.</li>
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</references>
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</qhelp>

‎ql/src/experimental/CWE-327/WeakCryptoAlgorithm.ql

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/**
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* @name Use of a weak cryptographic algorithm
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* @description Using weak cryptographic algorithms can allow an attacker to compromise security.
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* @kind path-problem
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* @problem.severity error
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* @id go/weak-crypto-algorithm
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* @tags security
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* external/cwe/cwe-327
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*/
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import go
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import WeakCryptoAlgorithmCustomizations::WeakCryptoAlgorithm
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import DataFlow::PathGraph
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from Configuration cfg, DataFlow::PathNode source, DataFlow::PathNode sink
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where cfg.hasFlowPath(source, sink)
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select sink.getNode(), source, sink, "$@ is used in a weak cryptographic algorithm.",
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source.getNode(), "Sensitive data"

‎ql/src/experimental/CWE-327/WeakCryptoAlgorithmCustomizations.qll

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/**
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* Provides default sources, sinks and sanitizers for reasoning about
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* sensitive information in weak cryptographic algorithms,
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* as well as extension points for adding your own.
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*/
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import go
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private import semmle.go.security.SensitiveActions
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private import CryptoLibraries
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module WeakCryptoAlgorithm {
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/**
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* A data flow source for sensitive information in weak cryptographic algorithms.
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*/
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abstract class Source extends DataFlow::Node { }
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/**
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* A data flow sink for sensitive information in weak cryptographic algorithms.
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*/
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abstract class Sink extends DataFlow::Node { }
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/**
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* A sanitizer for sensitive information in weak cryptographic algorithms.
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*/
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abstract class Sanitizer extends DataFlow::Node { }
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/**
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* A sensitive source.
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*/
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class SensitiveSource extends Source {
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SensitiveSource() { this.asExpr() instanceof SensitiveExpr }
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}
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/**
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* An expression used by a weak cryptographic algorithm.
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*/
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class WeakCryptographicOperationSink extends Sink {
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WeakCryptographicOperationSink() {
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exists(CryptographicOperation application |
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application.getAlgorithm().isWeak() and
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this.asExpr() = application.getInput()
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)
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}
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}
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/**
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* A configuration depicting taint flow from sensitive information to weak cryptographic algorithms.
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*/
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class Configuration extends TaintTracking::Configuration {
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Configuration() { this = "WeakCryptoAlgorithm" }
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override predicate isSource(DataFlow::Node source) { source instanceof Source }
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override predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
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override predicate isSanitizer(DataFlow::Node node) {
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super.isSanitizer(node) or
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node instanceof Sanitizer
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}
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}
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}

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