Pentagon’s Warning on Signal: Security Risks and Implications for Classified Communications

The Pentagon recently issued a serious warning regarding the use of the messaging app Signal, citing significant security threats posed by Russian hackers, according to NPR. This memo circulated across the department just days before a controversial incident involving The Atlantic’s editor-in-chief, Jeffrey Goldberg. Goldberg was unintentionally included in a Signal group chat that discussed sensitive military operations targeting Houthi rebels in Yemen, with notable members such as U.S. Secretary of Defense Pete Hegseth and Vice President J.D. Vance present.

Understanding the Risks of Signal’s Linked Devices Feature

In its warning, the Pentagon highlighted that “Russian professional hacking groups are employing the ‘linked devices’ features to spy on encrypted conversations.” The linked devices functionality permits Signal users to access their accounts on multiple devices, ensuring that messages are synchronized seamlessly. Signal uses end-to-end encryption, storing messages only locally with an encryption key. The connection between devices is established securely through QR codes:

A single encryption key sent from the primary device to the new device serves to create a secure connection for sending encrypted data. By simply scanning a QR code on the new device, the process can be initiated efficiently.

The Exploitation of Signal’s Features by Hackers

The Pentagon memo warns that hackers are finding ways to exploit this feature through phishing attempts. They can create malicious QR codes or phishing pages linked to group chats. “Upon gaining access to this malicious code, hackers can add their own devices as linked devices,” the memo stated, allowing them to monitor unsuspecting users’ messages in real time, thereby bypassing the intended security of end-to-end encryption.

Comparing Signal and Telegram: Security Challenges in Messaging Apps

Another messaging platform, Telegram, has also faced similar security threats, particularly amid the ongoing conflict in Ukraine, with some organizations tied to the Kremlin offering a €4.7 million bounty for exploits. This indicates a broader trend of hacking threats targeting popular private messaging apps.

The Limitations of Consumer-Grade Encryption Tools

While Signal has defended its security measures and emphasized its commitment to protecting user data, it is important to recognize that no app—especially a consumer-grade one—can guarantee complete security for discussions involving classified information. It has become increasingly clear that using such platforms for sensitive political communications during global conflicts raises red flags. For this reason, governments have established Secure Compartmented Information Facilities (SCIFs) for discussing classified content.

Official Responses and Investigations Following the Incident

In light of these developments, White House Press Secretary Karoline Leavitt has asserted that no classified materials or war plans were discussed in the Signal chat. An investigation into how Goldberg was added to the conversation is currently underway, as she aims to quell public speculation.

Jeffrey Goldberg is well-known for his sensationalist spin. Here are the facts about his latest story:

1. No “war plans” were discussed.

2. No classified material was sent to the thread.

3. The White House Counsel’s Office has provided guidance on a number of different…

— Karoline Leavitt (@PressSec) March 25, 2025

Some critics have called out Goldberg for his presence in the chat during sensitive discussions, asserting that his journalistic duty includes exposing incompetence within governmental communication protocols. If proper procedures were followed, his involvement would likely have been avoided altogether.

Why Use Signal for Sensitive Communications?

This incident raises pressing questions about the rationale behind high-level officials using Signal for sensitive discussions. Press Secretary Leavitt suggested efficiency as a motivator for this decision. However, given the app’s notorious self-destructing messages feature, which could complicate record-keeping, this choice merits further scrutiny.

Frequently Asked Questions

What is the Pentagon’s warning about Signal?

The Pentagon warned that Russian hackers exploit Signal’s linked devices feature to gain unauthorized access to encrypted conversations, raising serious security concerns for sensitive communications.

How do linked devices work on Signal?

Linked devices enable users to access their Signal account on multiple devices, synchronizing incoming and outgoing messages. It uses encrypted QR codes for establishing secure connections between devices.

What are the risks of using messaging apps like Signal for classified discussions?

Using consumer-grade messaging apps for classified discussions is risky because they are not built for handling sensitive information. Security vulnerabilities can be exploited through phishing, and end-users can be targeted through social engineering.

Why did the incident involving Jeffrey Goldberg occur?

The incident occurred when Jeffrey Goldberg, the editor of The Atlantic, was mistakenly added to a Signal chat discussing military operations, highlighting communication protocol failures among high-level officials.

The ongoing debate surrounding the use of Signal and its reliability underscores the need for secure communication solutions that meet the demands of high-stakes environments where classified information is involved.