RCQ Messenger Duress PIN Flaw Gave Full Access to Real Database on Android
Developers of the open-source messenger RCQ published a detailed post-mortem on flaws in their duress PIN implementation. The feature, also known as panic PIN or decoy code, is intended to let users unlock a harmless version of the app when forced to hand over their device.
Both Android and iOS versions encrypt the local message database. The database key, called dataKey, is stored encrypted with a value derived from the user’s PIN using PBKDF2-HMAC-SHA256 with 400 000 rounds plus a platform-protected pepper. Multiple slots exist for the real PIN, the decoy PIN, and a wipe PIN; each slot was supposed to carry its own payload.
On Android the decoy slot originally stored the identical dataKey used by the real account. Hiding the second account was performed only by an in-memory filter, leaving the real .db files untouched on disk. Entering the decoy code therefore decrypted the genuine conversation history, giving the impression of protection while actually exposing everything.
The root cause traced back to an early design decision to make the decoy mode appear as a second legitimate account sharing the same database. Later analysis showed that server-side correlation via push tokens, IP addresses, and device identifiers would immediately link the two accounts anyway, rendering the shared-key approach both dangerous and unnecessary.
The iOS version avoided the shared-key mistake but introduced its own problem: activating decoy mode cleared contacts and groups, producing an obviously empty application that itself became evidence of concealment. Notifications also bypassed the decoy filter on both platforms, potentially revealing real incoming messages.
After the review the team adopted the iOS cryptographic model across platforms. The decoy slot now holds an independent random key that opens only a separate decoy database. This database is populated with locally generated, realistically dated conversations chosen by the user. No real network requests are possible from decoy mode, eliminating server-side linkage. Legacy slots are marked and require manual re-creation of the decoy PIN.
On desktop the Tauri application uses Argon2id (64 MB memory, 3 passes) to derive a key that encrypts a vault containing both account secrets and message history with AES-256-GCM. The web version deliberately offers no PIN protection because any script in the same origin can read localStorage and IndexedDB.
Related articles
Fuzzy Logic in Cybersecurity: Reducing Vulnerability Queue by 7.5 Times with CVSS, EPSS and FSTEC Comparison
An information security specialist has developed a fuzzy logic system that prioritizes vulnerabilities far more effectively than traditional scoring methods. The approach uses linguistic variables and membership functions to handle the inherent uncertainty in exploitability and impact assessments. By integrating EPSS probability data with CVSS impact scores and vulnerability age, the model reduces the actionable backlog by a factor of 7.5. The implementation relies on the Mamdani inference algorithm and trapezoidal membership functions to produce smooth, human-interpretable urgency ratings. Detailed coverage checks and rule-base validation ensure no gaps exist in the decision space. Real-world testing on CVE-2025-49113 in Roundcube Webmail demonstrated practical advantages over rigid threshold logic. The method is positioned as a practical enhancement rather than a replacement for existing standards.
VLC Media Player Hit by Two Memory Corruption Flaws Exploitable via Malicious PNG and Rogue RealRTSP Server
Two vulnerabilities have been discovered in the VLC media player that allow out-of-bounds memory access. The issues affect versions from 3.0.0 through 3.0.23. CVE-2026-56711, rated 8.6 on CVSS 4.0, stems from an integer overflow when calculating image buffer sizes in PNG files, enabling attackers to trigger writes beyond allocated memory simply by opening a crafted image or loading it from a playlist. CVE-2026-73324, scored 6.9, resides in the RealRTSP module and permits a malicious server to send an oversized response string that causes reads past the end of a buffer due to a missing null terminator. Both flaws are present in official VideoLAN builds, although some distributions may exclude the RealRTSP component. No special configuration or plugins are required to trigger the issues. Until patched releases appear, users are advised to avoid opening images or playlists from untrusted sources and to refrain from connecting to unknown RealRTSP streams.
September Windows 11 Security Update KB5124008 Breaks Always On VPN Certificate Authentication
The September security update KB5124008 for Windows 11 has introduced a regression that disables Always On VPN connections using certificate-based authentication. The issue affects devices running Windows 11 versions 24H2 and 25H2 that connect to Remote Routing and Access Service (RRAS) and Network Policy Server (NPS) instances on Windows Server 2019. VPN profiles deployed via Microsoft Intune are impacted, with the failure occurring during the certificate negotiation phase of the IPsec connection. Users confirm the problem is reproducible: the VPN works before the patch, stops after installation, and resumes after patch removal and reboot. Microsoft has not yet acknowledged the regression or released a fix, leaving administrators to pause deployment through WSUS or Intune and open support cases with client and NPS logs. A potential workaround involves switching profiles to EAP-TLS, though its reliability remains unconfirmed.
API Token Lifecycle: From Issuance to Revocation and Secure Management
The article provides a comprehensive examination of the full API token lifecycle in browser-based applications, emphasizing that signatures alone cannot prevent token theft. It details risks introduced at issuance, storage, transmission, and revocation stages, including improper OAuth grant types and long-lived tokens. Key recommendations include short-lived access tokens, atomic refresh token rotation, and the use of Authorization Code Flow with PKCE for public clients. Storage advice strongly discourages localStorage and sessionStorage in favor of HttpOnly cookies or a Backend-for-Frontend pattern that keeps real tokens on the server. The piece also covers CSRF protections, rate limiting on authorization endpoints, and the advantages of signed client assertions over static secrets. Overall, it stresses that token security depends on the entire lifecycle architecture rather than cryptographic strength alone.