CVE-2020-9934
Apple iOS, iPadOS, and macOS Input Validation Vulnerability
Description
CVE-2020-9934 is an input validation vulnerability in Apple iOS, iPadOS, and macOS that allows a local attacker to view sensitive user information. The flaw stems from improper input validation within the operating system, enabling unauthorized access to protected data such as the TCC (Transparency, Consent, and Control) database. By exploiting this vulnerability, an attacker with local access can bypass privacy protections and read sensitive user data without consent. CISA has added CVE-2020-9934 to its Known Exploited Vulnerabilities catalog, and with an EPSS score of 2.44% (85th percentile), exploitation activity has been observed in targeted attacks.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| apple | ipados | < 13.6 |
| apple | iphone os | < 13.6 |
| apple | mac os x | < 10.15.6 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
References
- https://support.apple.com/HT211288(Release Notes, Vendor Advisory)
- https://support.apple.com/HT211289(Release Notes, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9934(US Government Resource)
Weakness Type
CWE-20: Improper Input Validation
CVE-2020-9934 exploits an improper input validation weakness in Apple's operating systems, where user-supplied input is not correctly validated before being used in security-sensitive operations. In the context of iOS, iPadOS, and macOS, this allows an attacker to manipulate environment variables or input parameters to bypass the TCC privacy framework, gaining access to protected user data without triggering the expected consent prompts.
Learn more: CWE-20 — Improper Input Validation
Impact Analysis
CVE-2020-9934 represents a significant privacy threat to Apple device users. The vulnerability is exploitable locally, meaning the attacker needs some form of access to the target device, but once achieved, no user interaction is required to carry out the attack. The improper input validation flaw allows bypassing Apple's TCC framework, which is the core mechanism protecting access to contacts, photos, location data, microphone, camera, and other sensitive resources. With an EPSS score of 2.44% placing it in the 85th percentile, exploitation has been observed in targeted scenarios. While this vulnerability does not enable remote code execution on its own, it can be chained with other exploits to fully compromise user privacy on affected devices, making it a valuable component in advanced attack chains targeting Apple platforms.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2020-9934 in the wild by adding it to the Known Exploited Vulnerabilities catalog with a remediation deadline of September 29, 2022. The EPSS score of 2.44% (85th percentile) indicates moderate but non-trivial exploitation probability, consistent with targeted rather than mass exploitation campaigns. This vulnerability is particularly valuable in exploit chains targeting Apple devices, as TCC bypass capabilities allow attackers to silently access sensitive user data after gaining initial code execution through a separate vulnerability. No known ransomware campaigns have been associated with this vulnerability.
Remediation
- Apply Apple security updates immediately: Install iOS 13.6, iPadOS 13.6, and macOS Catalina 10.15.6 or later, which contain the fix for CVE-2020-9934 as documented in Apple security advisories HT211288 and HT211289.
- Audit all managed Apple devices for patch compliance: Ensure no devices in your fleet are running versions prior to the patched releases, particularly in enterprise environments where TCC bypass could expose sensitive corporate data.
- Restrict local access to Apple devices: Implement strong device authentication policies (complex passcodes, biometric authentication) and mobile device management (MDM) controls to limit the attack surface for local exploitation.
- Monitor for TCC database access anomalies: Review system logs for unusual access patterns to the TCC database (~/Library/Application Support/com.apple.TCC/TCC.db on macOS) that could indicate exploitation attempts.
- Implement defense-in-depth input validation: For enterprise application development on Apple platforms, validate all input parameters rigorously and avoid reliance on environment variables for security-critical decisions.
Technical Details
CVE-2020-9934 targets Apple's Transparency, Consent, and Control (TCC) framework, which manages user privacy permissions for accessing sensitive resources such as the camera, microphone, contacts, and location services. The vulnerability exists because the operating system fails to properly validate certain input parameters — specifically environment variables — that influence how the TCC daemon processes access requests. An attacker with local access can manipulate these environment variables to cause the TCC framework to load a malicious or attacker-controlled TCC database, effectively replacing the legitimate permission store with one that grants blanket access to all protected resources. This input validation failure means the system does not verify the integrity or source of the TCC database path, allowing the attacker to point the framework to an arbitrary file. The fix implemented by Apple in iOS 13.6 and macOS Catalina 10.15.6 addresses this by properly validating the TCC database source and removing the ability to override it via environment variables.
Frequently Asked Questions
Is CVE-2020-9934 being actively exploited?
Yes. CISA has added CVE-2020-9934 to its Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The vulnerability is used in targeted attacks to bypass Apple's privacy protections and access sensitive user data without consent. No ransomware campaigns are currently associated with this vulnerability.
What products are affected by CVE-2020-9934?
CVE-2020-9934 affects Apple iOS (versions before 13.6), iPadOS (versions before 13.6), and macOS Catalina (versions before 10.15.6). All Apple devices running these older operating system versions are vulnerable to the TCC bypass attack.
How do I fix CVE-2020-9934?
Update all affected Apple devices to iOS 13.6, iPadOS 13.6, or macOS Catalina 10.15.6 or later. These releases patch the input validation flaw in the TCC framework. Additionally, restrict local device access and monitor for anomalous TCC database access patterns.
How severe is CVE-2020-9934?
CVE-2020-9934 is a significant privacy vulnerability that allows local attackers to bypass Apple's core privacy protection framework. With an EPSS score of 2.44% (85th percentile) and confirmed exploitation in the wild, it poses a real threat particularly in targeted attack scenarios. The vulnerability enables access to protected data including contacts, photos, location, and camera without user consent.
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