CVSS Vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Lifecycle Timeline
3Description
The Postbox's configuration on macOS, specifically the presence of entitlements: "com.apple.security.cs.allow-dyld-environment-variables" and "com.apple.security.cs.disable-library-validation" allows for Dynamic Library (Dylib) injection. A local attacker with unprivileged access can use environment variables like DYLD_INSERT_LIBRARIES to successfully inject code in application's context and bypass Transparency, Consent, and Control (TCC). Acquired resource access is limited to previously granted permissions by the user. Access to other resources beyond granted-permissions requires user interaction with a system prompt asking for permission. The original company behind Postbox is no longer operational, the software will no longer receive updates. The acquiring company (em Client) did not cooperate in vulnerability disclosure.
Analysis
The Postbox's configuration on macOS, specifically the presence of entitlements: "com.apple.security.cs.allow-dyld-environment-variables" and "com.apple.security.cs.disable-library-validation" allows for Dynamic Library (Dylib) injection. A local attacker with unprivileged access can use environment variables like DYLD_INSERT_LIBRARIES to successfully inject code in application's context and bypass Transparency, Consent, and Control (TCC). Acquired resource access is limited to previously granted permissions by the user. Access to other resources beyond granted-permissions requires user interaction with a system prompt asking for permission.
The original company behind Postbox is no longer operational, the software will no longer receive updates. The acquiring company (em Client) did not cooperate in vulnerability disclosure.
Technical Context
Privilege escalation allows a low-privileged user or process to gain elevated permissions beyond what was originally authorized. This vulnerability is classified as Incorrect Default Permissions (CWE-276).
Remediation
Apply the principle of least privilege. Keep systems patched. Monitor for suspicious privilege changes. Use mandatory access controls (SELinux, AppArmor).
Priority Score
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-28697