This blog post analyzes "TM Sgnl," an Android app marketed as a secure messaging platform used by some Trump officials, including Mike Waltz. The author reverse-engineered the app, revealing it relies on the open-source Signal protocol but lacks crucial security features like forward secrecy and disappearing messages. Furthermore, TM Sgnl uses its own centralized server, raising concerns about data privacy and potential vulnerabilities compared to the official Signal app, which uses a federated server architecture. The analysis concludes that despite presenting itself as a secure alternative, TM Sgnl likely offers weaker security and potentially exposes user data to greater risk.
This in-depth technical analysis delves into the intricacies of "TM Sgnl," a purportedly secure messaging application utilized by former Trump administration officials, including Congressman Mike Waltz. The author meticulously dissects the application, revealing that it is not, in fact, affiliated with the widely recognized and respected Signal Private Messenger. Instead, it is a bespoke, closed-source variant built upon an obscure, open-source project known as "LibreSignal." This distinction raises significant concerns regarding security and privacy.
The analysis painstakingly traces the application's lineage, highlighting the developer's modifications to the original LibreSignal codebase. These alterations include the removal of crucial security features, specifically the functionality for verifying the identity of contacts. This omission introduces a critical vulnerability: users cannot be certain they are communicating with their intended recipient, leaving them susceptible to man-in-the-middle attacks and potential impersonation.
Furthermore, the investigation reveals that TM Sgnl lacks the robust end-to-end encryption that is a hallmark of genuine Signal. While the application employs encryption for data transmission, the server managing the communication holds the decryption keys. This architectural choice grants the server administrator, and potentially any entity gaining access to the server, the ability to decipher and read all messages passing through the system. This fundamentally compromises the confidentiality of communications, a stark contrast to Signal's decentralized approach that ensures only the communicating parties possess the decryption keys.
The author meticulously documents the process of reverse-engineering the Android application package (APK), outlining the steps taken to decompile the code and analyze its behavior. This detailed walkthrough provides valuable insights into the inner workings of TM Sgnl, showcasing the extent of the developer's modifications and their implications for security. The analysis underscores the potential risks associated with using closed-source messaging applications, especially when those applications deviate significantly from established security best practices and lack transparent auditing mechanisms.
Finally, the investigation brings to light the questionable practices employed in distributing the application. TM Sgnl is not available through official app stores, a red flag that further amplifies concerns about its security posture. The application is instead distributed through direct downloads, a method that bypasses the vetting processes employed by app stores and increases the risk of users inadvertently installing malicious software. This unorthodox distribution method, coupled with the aforementioned security vulnerabilities, paints a concerning picture of the application's trustworthiness and raises serious questions about the suitability of TM Sgnl for sensitive communications.
Summary of Comments ( 249 )
https://news.ycombinator.com/item?id=43875476
HN commenters discuss the implications of using an obscure, unofficial Signal fork, TM-SGNL, by Trump officials. Several express concerns about the security and trustworthiness of such a client, particularly given its lack of transparency and potential for vulnerabilities. Some question the choice, suggesting it stems from a misunderstanding of Signal's functionality, specifically the belief that official servers could access their data. Others point out the irony of using a supposedly more secure app while simultaneously broadcasting its usage, potentially defeating the purpose. The feasibility of sideloading this app onto government-issued devices is also debated. A few comments highlight the difficulty of truly secure communication, even with robust tools like Signal, if operational security practices are poor. The discussion also touches on the broader issues of government officials' use of encrypted messaging and the challenges of balancing transparency and privacy.
The Hacker News thread linked discusses the article about TM Sgnl, an unofficial Signal fork used by Trump officials. The comments are generally critical of TM Sgnl and skeptical of its security.
One of the most compelling lines of discussion revolves around the security implications of using a closed-source, unofficial fork of Signal. Commenters highlight the inherent risks, emphasizing that without open-source code for scrutiny, there's no way to verify the claimed security features. The lack of transparency raises suspicion, especially given the sensitivity of communications involving government officials. Some speculate that the app might contain backdoors or vulnerabilities, intentionally or unintentionally, that could compromise sensitive information. The closed nature of the app makes independent security audits impossible, further amplifying concerns. One commenter specifically mentions the lack of reproducible builds, meaning it's impossible to verify that the distributed application matches the supposedly audited source code, even if it were made available.
Several comments also delve into the technical aspects of Signal and why forking it is problematic. They explain how Signal's security relies heavily on the open-source nature of its protocol and implementation. Forking the code and then modifying it, especially without public scrutiny, introduces the possibility of inadvertently weakening security. The commenters argue that even seemingly minor changes could have unforeseen consequences. This point underscores the importance of the open-source community in identifying and patching vulnerabilities.
Another thread focuses on the motivations behind using TM Sgnl. Speculation ranges from genuine, though misplaced, concerns about data privacy to a desire for more control over communication and potentially bypassing official channels. Some comments suggest a lack of understanding about Signal's existing security features might have led to the adoption of the fork, while others are more cynical, hinting at possible deliberate attempts to circumvent scrutiny.
Finally, some comments address the legal and ethical implications of government officials using an unvetted communication platform. They raise questions about transparency and accountability, particularly when public figures are involved.
Overall, the comments express a strong sense of skepticism and concern about the security and motivations behind the use of TM Sgnl. They highlight the importance of open-source software for secure communication, especially in sensitive contexts, and raise critical questions about the potential risks associated with closed-source alternatives.