CVE-2024-0727 is a medium-severity vulnerability in OpenSSL affecting multiple versions including 3.2.0, 3.1.0, 3.0.0, 1.1.1, and 1.0.2. The issue arises from improper handling of PKCS12 files, which are commonly used to bundle certificates and private keys. Specifically, OpenSSL does not correctly check for NULL pointers in certain fields allowed by the PKCS12 specification. When processing a maliciously crafted PKCS12 file containing NULL fields, OpenSSL’s vulnerable APIs (PKCS12_parse(), PKCS12_unpack_p7data(), PKCS12_unpack_p7encdata(), PKCS12_unpack_authsafes(), and PKCS12_newpass()) may dereference a NULL pointer, causing the application to crash. This results in a denial of service (DoS) condition. The vulnerability does not impact confidentiality or integrity but affects availability by causing abrupt termination of applications that load PKCS12 files from untrusted sources. Notably, the FIPS modules in OpenSSL versions 3.0, 3.1, and 3.2 are not affected. Although a similar issue was fixed in SMIME_write_PKCS7(), it is not considered security significant as it relates to data writing rather than parsing. No known exploits are reported in the wild at this time. The vulnerability requires user interaction in the form of loading a malicious PKCS12 file and has a CVSS v3.1 base score of 5.5, reflecting its medium severity. The attack vector is local, requiring the attacker to supply a crafted file to the vulnerable application, which must then process it using the affected OpenSSL APIs.

For European organizations, the primary impact of CVE-2024-0727 is the potential for denial of service in applications that utilize OpenSSL to parse PKCS12 files from untrusted or external sources. This can disrupt services that rely on certificate management, such as secure communications, VPNs, email encryption, and identity management systems. Organizations handling large volumes of certificates or automating certificate imports are particularly at risk if these processes do not validate input files properly. While the vulnerability does not allow data theft or code execution, the availability impact could lead to operational disruptions, especially in critical infrastructure sectors like finance, healthcare, and government where PKCS12 files are commonly used for secure key storage. The lack of known exploits reduces immediate risk, but the widespread use of OpenSSL in European IT environments means the vulnerability could be leveraged in targeted attacks or cause accidental outages if malicious or malformed files are introduced, intentionally or otherwise.

European organizations should implement the following specific mitigations: 1) Immediately update OpenSSL to a patched version once available, or apply vendor patches if using third-party software that bundles OpenSSL. 2) Restrict the sources of PKCS12 files to trusted and verified origins; implement strict input validation and file integrity checks before processing. 3) Employ sandboxing or isolation techniques for applications that parse PKCS12 files to contain potential crashes and prevent broader service disruption. 4) Monitor application logs for crashes or abnormal terminations related to PKCS12 processing to detect exploitation attempts or accidental triggers. 5) For critical systems, consider using the OpenSSL FIPS modules (3.0, 3.1, 3.2) which are not affected by this vulnerability. 6) Educate administrators and users about the risks of loading PKCS12 files from untrusted sources and enforce policies to prevent such practices. 7) If feasible, implement application-level exception handling around OpenSSL PKCS12 parsing calls to gracefully handle errors and maintain service availability.