Security researchers have raised concerns over how WhatsApp stores user chat data on macOS and iOS, revealing that message databases may be stored in unencrypted form within app group containers accessible by other applications from the same developer ecosystem.
According to researchers at Mysk, WhatsApp stores chat histories in plaintext within a shared app group container. On Apple platforms, app group containers enable data sharing between applications signed by the same developer.
In this case, Meta-owned apps such as Facebook, Instagram, and WhatsApp reportedly share a common container identified as “group.com.facebook.family.”
This architecture introduces potential privacy risks:
- Chat databases are stored at rest without encryption.
- Other Meta apps on the same device could, in theory, access WhatsApp data without explicit user consent.
- No user notification mechanism exists for this type of access.
- The issue applies to both macOS and iOS environments.
Researchers demonstrated that users can extract WhatsApp chat data from iPhone backups, where the same unencrypted structure is visible, confirming the lack of encryption at rest.
macOS Sandbox Bypass Amplifies Risk
The exposure risk is further compounded by a recently disclosed macOS vulnerability (CVE-2026-28910) affecting the Archive Utility tool. The flaw allowed near-unrestricted filesystem access and could bypass Apple’s App Sandbox protections.
By exploiting this weakness, attackers could potentially:
- Access protected app containers.
- Extract sensitive data from applications like WhatsApp, Messages, and Safari.
- Bypass Transparency, Consent, and Control (TCC) safeguards.
A proof-of-concept demonstration showed how attackers could exploit this flaw, along with WhatsApp’s storage behavior, to access chat histories.
Not all experts agree on the severity of the issue. WABetaInfo noted that while WhatsApp databases may not be encrypted locally, they are still stored within Apple’s sandboxed environment, which is designed to prevent unauthorized access.
From this perspective:
- Access to the container requires either system-level privileges or exploitation of OS vulnerabilities.
- The responsibility for preventing cross-app data access lies primarily with Apple’s operating system protections.
However, Mysk counters that shared app group entitlements between Meta applications weaken isolation boundaries, enabling internal data sharing without user awareness.
The findings highlight a broader concern around data-at-rest protection in mobile ecosystems:
- End-to-end encryption protects data in transit but does not guarantee local storage security.
- Shared containers increase the attack surface when combined with OS-level flaws.
- Backup extraction remains a viable method for accessing sensitive data if not encrypted.
Mitigation Recommendations
Users and organizations can reduce exposure risk by:
- Enabling encrypted iTunes or Finder backups for iOS devices.
- Keeping macOS and iOS up to date to patch known vulnerabilities.
- Limiting the number of installed apps from the same developer ecosystem.
- Use device-level encryption and strong passcodes.
While no active exploitation has been widely reported, the research underscores the importance of securing sensitive data both in transit and at rest, especially in tightly integrated app ecosystems like Meta’s.
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