Description

openssl_encrypt (pip package openssl-encrypt) versions 1.4.8 and earlier store an mTLS client private key in cleartext within a world-readable (0644) SharedPreferences file via the desktop GUI's Settings screen 'combined certificate and private key' PEM field. A local attacker with file system access can read the exposed private key. Version 1.4.9 writes the PEM to a dedicated 0600 file, keeps only its path in SharedPreferences, and migrates/scrubs existing cleartext values.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.4",
  "pubDate": "2026-08-27T17:20:57.810Z",
  "pubdate": "2026-08-27T17:20:57.810Z",
  "executiveSummary": "The openssl-encrypt pip package contains a critical vulnerability related to the insecure storage of mTLS client private keys. Versions 1.4.8 and earlier persist sensitive PEM-encoded private keys in cleartext within SharedPreferences files configured with world-readable (0644) file permissions.\nThis vulnerability exposes the cryptographic material to any local user or malicious process with file system access on the host machine. The impact of this flaw is significant, as a compromised private key allows an attacker to impersonate the legitimate client, bypass authentication mechanisms, and perform unauthorized actions within an mTLS-secured communication channel.\nThe attack is passive and requires only local file system access, necessitating no interaction from the targeted user. The risk is classified as high due to the sensitivity of the stored credentials and the accessibility of the underlying storage mechanism.",
  "technicalDetails": "The vulnerability originates in the desktop GUI's Settings screen implementation, specifically within the handling of the 'combined certificate and private key' PEM field. In versions 1.4.8 and earlier, the package architecture incorrectly utilizes the application's SharedPreferences file to store this sensitive data. By default, these files are assigned permissions (0644) that grant read access to all users on the operating system.\nThe root cause is an improper credential management lifecycle where sensitive private key material is stored in a location shared with application settings rather than a dedicated, secure, and restricted storage medium. Because SharedPreferences is not intended for the persistent storage of secrets without additional encryption or restricted access controls, the cleartext PEM data remains discoverable to any local attacker.\nThe attack flow follows a predictable pattern: 1) An attacker gains local access to the file system where the openssl-encrypt application is deployed. 2) The attacker navigates to the directory containing the application's SharedPreferences configuration files. 3) By parsing the XML-based or serialized SharedPreferences content, the attacker identifies the 'combined certificate and private key' entry. 4) The attacker extracts the cleartext PEM string. 5) Once obtained, the attacker uses the extracted key to establish unauthorized mTLS sessions, effectively masquerading as the legitimate entity.\nThis vulnerability is remediated in version 1.4.9. The updated version implements a secure architecture where the sensitive PEM data is written to a dedicated file restricted to 0600 permissions, ensuring only the owner can access the file content. SharedPreferences is updated to contain only a reference path to this secure file. Furthermore, the 1.4.9 release includes logic to migrate existing keys from the insecure SharedPreferences storage to the new, secure file location and subsequently scrub the cleartext values from the insecure storage.\nExploitation does not require elevated privileges beyond basic file system read access; it does not require network exposure, as the theft occurs entirely at rest on the local host. Post-exploitation allows the adversary to maintain persistent authentication capabilities, potentially leading to unauthorized access to secured backend services protected by the mTLS handshake."
}