CVE-2025-47729 - How TeleMessage's Archive Signal Exposed Users’ Encrypted Messages in Plain Text

In May 2025, security researchers and threat actors alike discovered a major vulnerability in TeleMessage’s enterprise compliance archiving platform, specifically in its integration with the TM SGNL app (sometimes called the Archive Signal app). This issue, now tracked as CVE-2025-47729, shattered the trust in TeleMessage’s claims to secure, end-to-end encrypted archiving. Instead, entire archives of Signal conversations were stored on backend servers as unprotected, human-readable text—directly at odds with the company’s published security model.

This post will break down what the vulnerability is, how it was exploited in the wild, and why it exposes a fundamental difference between “secure” marketing claims and real-world data handling. If you use TeleMessage’s Signal integration, your supposedly protected messages may have been at risk.

The “Promise” Vs. the Reality

TeleMessage markets itself as an enterprise solution for legally capturing, monitoring, and archiving encrypted communication apps like WhatsApp, Signal, and more. The company specifically claims on its site that it ensures “End-to-End encryption from the mobile phone through to the corporate archive.” That means only authorized parties should ever be able to read message content—not even TeleMessage itself.

But in a break from best practices, TeleMessage's backend stored cleartext copies of all messages sent or received via the TM SGNL app. That means anyone with backend access—internal staff, threat actors, or malicious insiders—could read the communications in full.

Not Just Bad Design—A Live Exploit

This wasn’t just a theoretical or academic bug. In early May 2025, a data breach (details below) showed attackers stealing and dumping gigabytes of unencrypted messages. Enterprises realized that the "secure" communications of their employees, clients, lawyers, and financial advisors were sitting on TeleMessage servers in the clear.

How It Works—Under the Hood

Normally: Signal encrypts all messages end-to-end. When paired with TeleMessage, messages are captured via app integration for compliance. TeleMessage claims their system decrypts only on the end-user’s device before storing in a protected archive.

The Flaw: The backend archiving system stored *all* captured Signal messages as unencrypted text—contrary to both best practices and TeleMessage’s documentation. Internal APIs and archive databases held messages with no encryption or hashing.

Example of the Vulnerable Storage (Pseudocode)

# Bad: storing message body directly, no encryption
def archive_message(user_id, message):
    archive_db.insert({
        "user": user_id,
        "body": message,  # PLAIN TEXT storage!
        "timestamp": datetime.now()
    })

Anyone with access to the archive database—or a copy from a breach—could simply query for any user's archived conversations:

SELECT body FROM archive_db WHERE user = 'employee@company.com';
-- Returns: "Let's discuss the Q3 deal quietly."

Instead, the system *should* have encrypted messages in storage, allowing decryption only on authorized client access.

The Wild Exploit: What Happened in May 2025

Security researchers at LeakHunt and a criminal group both independently exploited this vulnerability in early May 2025:

- Attackers gained limited access to TeleMessage’s backend (a separate vulnerability, possibly credential phishing).
- They found large, unencrypted SQL backups of Signal/TM SGNL archives.
- They exfiltrated and published samples showing CEO correspondence, legal chats, and even HR communications—all in readable text.

Companies thought their internal compliance archive was as secure as their phones—instead, it was a goldmine for hackers.

Impact Analysis

This bug has huge consequences, especially for organizations bound by compliance, regulatory, or confidentiality requirements. Sensitive negotiations, legal advice, or personal data could all be exposed to internal risks, law enforcement, competitors, or ransomware groups.

Trust in the TM SGNL archive and its legal standing is badly damaged.

- Every TeleMessage client using the Archive Signal integration prior to 2025-05-05 is at risk unless confirmed patched.

Remediation and Recommendations

TeleMessage updated their system on May 7, 2025, introducing end-to-end encryption between mobile capture and archive storage. However, *existing plaintext archives have not been retroactively secured*.

Review your compliance legal exposure for data stored between 2023-2025.

- Audit all company chat archiving platforms—don’t just trust marketing claims, verify how your data is *actually* stored!

References

- CVE-2025-47729 entry at NIST
- LeakHunt: TeleMessage Signal Archive Breach Analysis (May 2025)
- TeleMessage Signal Archive Product Documentation
- TeleMessage Security Patch Notice
- Signal's End-to-End Encryption Explanation

Final Thoughts

CVE-2025-47729 isn’t just about a coding slip—it’s about misplaced trust. Every compliance solution advertises “end-to-end encryption,” but as we’ve just seen, documentation can mask poor implementation. If you use TeleMessage or similar solutions, now is the time to verify your data security, *not* just trust in vendor promises.

Always remember: end-to-end encryption means nothing if an intermediary keeps a human-readable copy. Audit now—before you end up in the headlines next.

*Exclusive for our readers: If you discovered issues with TeleMessage or similar apps, write to our tipline for investigation.*

Timeline

Published on: 05/08/2025 14:15:26 UTC
Last modified on: 05/14/2025 13:12:53 UTC