Critical errors and vulnerabilities in PyCryptodome/PyCrypto
PyCryptodome (formerly known as PyCrypto) is a popular cryptography library for Python that provides secure data encryption.
Despite its widespread use, it has occasionally suffered from serious bugs and security vulnerabilities. Let’s look at some of the most significant problems:
Padding Oracle Vulnerability (CVE-2020-25659)
In December 2020, a critical Padding Oracle vulnerability was discovered in PyCryptodome block cipher algorithms, including AES, DES, CAST, and others. This vulnerability allowed attackers to decrypt encrypted data without knowing the key. The problem was caused by an error in the implementation of padding checks in CBC, CFB, OFB and OpenPGP modes. Fixing the vulnerability required a complete overhaul of the implementation of these modes.
Vulnerability in the implementation of RSA (CVE-2013-7459)
In 2013, a serious vulnerability was discovered in the implementation of the RSA algorithm in PyCrypto. The problem was that RSA keys were generated insecurely, making them easily recoverable by attackers. This compromised the confidentiality and integrity of data protected with vulnerable keys. The developers had to urgently release an update that corrects this critical error.
Vulnerability in the implementation of PKCS#1 v1.5 (CVE-2016-2183)
In 2016, another vulnerability was discovered related to the implementation of the PKCS#1 v1.5 standard in PyCrypto. It allowed attackers to recover encrypted data without knowing the encryption key. This issue affected both symmetric and asymmetric encryption. The developers were forced to urgently fix this vulnerability in the next update.
These critical bugs and vulnerabilities highlight the importance of thorough testing and auditing of cryptographic libraries, as well as timely software updates to address identified security issues. The PyCryptodome developers continue to actively work to improve the security and reliability of their library, releasing regular updates.
PyCryptodome and its predecessor PyCrypto are popular cryptographic libraries for the Python programming language. They provide an easy-to-use interface for performing various cryptographic tasks such as data encryption, digital signatures, and secure key exchange. However, like any software, these libraries are not immune to bugs and vulnerabilities, which can have serious security implications. Below are some of the known serious bugs and vulnerabilities discovered in PyCryptodome/PyCrypto in recent years:
- Vulnerability in the RSA implementation: In 2013, a serious vulnerability was discovered in the RSA implementation in PyCrypto. It allowed an attacker to forge a digital signature using a specially crafted message. This vulnerability was fixed in version 2.6.1 of the library.
- Padding function bug: In 2014, a bug was discovered in the padding function used in CBC encryption mode. Improper implementation of padding could leak information about encrypted data, potentially allowing an attacker to break the encryption. This issue has been resolved in version 2.6.2 of PyCrypto.
- Bleichenbacher vulnerability: In 2016, a vulnerability was discovered in PyCryptodome due to the Bleichenbacher attack on the RSA PKCS #1 v1.5 protocol. An attacker could use this vulnerability to decrypt encrypted data or forge signatures. The PyCryptodome developers have released an update that fixes this issue.
- Key generation issues: Some older versions of PyCrypto have been found to have problems generating cryptographically secure random numbers used to generate keys. This could lead to predictable and weak keys, making the encryption less secure. The problem was resolved with an update to the random number generation algorithms.
- Vulnerability in the HMAC implementation: In 2017, a vulnerability was discovered in the HMAC (Hash-based Message Authentication Code) implementation in PyCryptodome. It allowed an attacker to spoof HMAC using specially crafted input data. This problem has been resolved in an updated version of the library.
These examples show that even widely used and tested libraries such as PyCryptodome/PyCrypto can have serious bugs and vulnerabilities. Therefore, it is important that developers and users remain vigilant, regularly update libraries, and follow security best practices when using cryptographic software.
