Why Yesterday’s Forgotten Security Lessons Keep Returning as Tomorrow’s Threats
I have been working in public safety communications and technology for 45 years.
During that time, I have watched equipment change, networks evolve, software become more sophisticated, and entire industries reinvent themselves around new acronyms.
But I have also watched the same mistakes return.
Sometimes they come back wrapped in newer technology. Sometimes they are hidden beneath an IP interface, a cloud platform, or a modern graphical dashboard. Sometimes they are rediscovered entirely by accident.
The equipment changes.
The underlying mistake often does not.
That is why silence is not golden.
When a system behaves unexpectedly, activates without authorization, or accepts a command from somewhere it was never expected to receive one, we need to talk about it. We need to investigate it, document it, publicize the lesson, and make certain the next generation of technologists understands what happened.
Keeping quiet does not eliminate the vulnerability.
It merely preserves it for the next person who discovers it—and that person may not be wearing a white hat.
When the Weather Hacked the Siren
As I covered in my recent blog on TiPS: Today in Public Safety, the recent incident in Huntington County, Indiana, about how unusual atmospheric conditions carried a radio signal roughly 300 miles from Iowa, accidentally activating a local warning siren.
That was a meteorological event called tropospheric ducting that caused the problem.
For this discussion, the key point is simple:
No firewall was breached.
No endpoint was infected.
No password was stolen.
The command arrived through the antenna, matched what the receiver expected, and the system responded.
The incident was accidental, not malicious. But it proved that the command pathway could be reached from outside its assumed boundary.
An accident can reveal a vulnerability before an attacker decides to reproduce it deliberately.
Dallas Had Already Shown Us the Other Side (Thanks to (@John Chiaramonte)
Way back in 2017, all 156 outdoor warning sirens in Dallas were maliciously activated late at night. The sirens sounded repeatedly until officials shut down portions of the system.
Initial reporting led many people to assume that attackers had penetrated a city computer system. Dallas officials later clarified that the incident involved spoofed radio signaling used by the siren-control network—not a conventional intrusion into the city’s software or IP infrastructure.
Dallas demonstrated the deliberate version of what Huntington County later demonstrated accidentally.
In Dallas, someone apparently transmitted something the sirens recognized as a valid command.
In Huntington County, atmospheric conditions carried something the siren recognized as a valid command.
The intent was different.
The underlying trust problem was remarkably similar.
The receiver heard the correct signal and acted.
That is not authentication.
That is recognition.
And the two are not the same.
The Telephone Network Learned This Lesson Decades Ago
None of this is really new.
Long before most people had heard the words cybersecurity, zero trust, or multifactor authentication, telephone phreakers discovered that portions of the long-distance telephone network relied on audible signaling tones carried through the same channel used for human conversation.
The network heard specific tones and treated them as instructions.
The problem was that the tones themselves were accessible to the customer.
Once someone understood the language, the network could not reliably distinguish between an authorized signal produced by telephone switching equipment and the same sound produced by a person, a recording, a whistle, or an electronic tone generator.
John Draper—better known as “Cap’n Crunch”—became one of the most recognizable figures from that era. A toy whistle distributed in boxes of Cap’n Crunch cereal could produce a tone near 2600 Hz, which was significant in portions of the long-distance signaling network. Draper did not originate phone phreaking, but the whistle and his nickname became enduring symbols of it.
The famous blue box generated tones used to manipulate long-distance trunks.
The red box imitated payphone coin-deposit tones.
The black box manipulated electrical conditions on a telephone line in ways that could interfere with billing.
There were many other colors, some representing genuine devices and techniques and others becoming part of phreaker slang, experimentation, or folklore.
The details are historically interesting, but the colored boxes are not the central lesson.
The central lesson is this:
The telephone network accepted correctly formed sounds as authority.
Once outsiders understood those sounds, they could reproduce them.
The network did not know who generated the tone.
It only knew that the tone was correct.
Over time, the industry moved critical interoffice signaling away from the subscriber’s audible channel and toward separate, out-of-band common-channel signaling systems. That transition helped eliminate the conditions that made traditional blue-box manipulation possible. (Wikipedia)
The telephone industry learned that a tone is not an identity.
Modern infrastructure should not have to learn that lesson all over again.
A Correct Code Does Not Prove Authority
Consider a four-digit ATM PIN.
Mathematically, four digits provide 10,000 possible combinations, ranging from 0000 through 9999.
That sounds reasonably broad until human behavior enters the equation.
People do not select numbers uniformly at random. They choose birthdays, birth years, repeated digits, memorable sequences, and recognizable keypad patterns.
The theoretical search space may contain 10,000 possibilities.
The practical search space becomes much smaller when an attacker understands how people behave.
The same principle applies to radio and audio control systems.
A signaling protocol may technically allow thousands or millions of possible code combinations. But if the valid command is static, predictable, reused, observable during testing, or easily recorded, the theoretical number of possible codes provides little comfort.
The attacker does not need to try every possible combination.
The attacker needs the one that works.
A correct PIN proves that someone knows the PIN.
It does not prove that the person entering it is the account owner.
A correct radio code proves that someone transmitted the code.
It does not prove that the sender was the authorized controller.
ATMs compensate for this weakness with other controls. They limit attempts. They retain the card. They monitor transactions. They may trigger fraud analytics or account alerts.
Many legacy radio receivers and tone-controlled systems do not have comparable protections. They may need to remain continuously receptive because their operational purpose is to respond immediately when a command arrives.
That makes independent authentication even more important.
The Clear, Open Channel
Cybersecurity teams have become very good at watching familiar digital pathways.
We monitor firewalls.
We inspect endpoints.
We collect application logs.
We deploy intrusion-detection systems, identity management, multifactor authentication, behavioral analytics, and security information and event management platforms.
All of that is necessary.
But it can also create a dangerous sense of completeness.
You can monitor every firewall, endpoint, and application log in the building and still miss the command that arrived through a clear, open channel—such as an antenna or audio input.
That channel might be:
- A radio receiver listening for an activation code.
- A microphone connected to a tone decoder.
- An audio input on a broadcast or alerting system.
- A wireless utility controller.
- A railway emergency radio.
- A building-control receiver.
- A field telemetry radio.
- A legacy interface wrapped inside an otherwise modern platform.
The command may never traverse the monitored IP network.
It may generate no failed login.
It may leave no conventional cybersecurity log.
The physical system simply responds.
This is not hypothetical.
In 2023, unauthorized radio transmissions activated an emergency-stop function on Poland’s railway system. Multiple trains were halted, and authorities investigated a series of disruptions involving the railway’s radio-stop mechanism. Two people were arrested in connection with some of the transmissions. (Reuters)
Once again, the infrastructure responded to a command it recognized.
The railroad stopped because that was exactly what it was designed to do.
The weakness was not that the safety function existed.
The weakness was that the system could not adequately distinguish between an authorized emergency command and an unauthorized imitation.
New Technology Can Preserve Old Assumptions
One of the dangers in technology modernization is that we replace the visible parts of a system without replacing the trust assumptions underneath them.
A modern control center may have:
- A web-based interface.
- Cloud-hosted management.
- Encrypted IP connectivity.
- Centralized logging.
- Role-based access.
- A polished dashboard.
Yet somewhere at the edge, the final device may still respond to a reusable tone, an unauthenticated radio sequence, a closure on an audio circuit, or a signaling method designed decades earlier.
The modern platform can make the overall system look secure while the oldest pathway remains open.
That is why younger technologists need the history.
History is not trivia.
History is operational knowledge.
The engineers who moved telephone signaling out of the subscriber’s voice path did so for a reason. The people who developed better authentication, encryption, challenge-response protocols, replay protection, sequence validation, source verification, and layered controls did so because earlier systems had failed.
When we remember only the modern solution and forget the failure that produced it, we become vulnerable to rebuilding the original mistake.
Why White Hats Matter
White-hat researchers are sometimes criticized for publicizing weaknesses.
There is always a legitimate discussion to be had about timing, responsible disclosure, technical detail, remediation, and whether publication creates unnecessary risk.
But silence carries risk too.
A vulnerability does not begin to exist when a researcher describes it.
It existed before the researcher found it.
Responsible security research gives manufacturers, operators, and public agencies an opportunity to understand the problem before a malicious actor quietly takes advantage of it.
That does not mean publishing every frequency, activation code, procedural weakness, or step-by-step exploitation method before mitigations are available.
It means acknowledging that the weakness exists.
It means notifying the responsible parties.
It means testing assumptions.
It means fixing the design.
It means sharing enough of the lesson that others operating similar systems know to look for the same condition.
Security through silence is not security.
Security through obscurity eventually fails when the obscure detail becomes observable, recordable, searchable, purchasable, or accidentally rediscovered.
Software-defined radios have lowered the cost of receiving, recording, studying, and reproducing many kinds of wireless signals. Knowledge that once required specialized equipment and institutional access is increasingly available to hobbyists, researchers, and attackers.
The answer is not to stop talking.
The answer is to design systems that remain secure even after people understand how they work.
Publicize the Accident Before Someone Repeats It Deliberately
The Huntington County siren incident should be treated as a gift—an uncomfortable one, but a gift nonetheless.
The system revealed an assumption.
The presumed radio boundary was not absolute.
The valid activation pattern could arrive from somewhere unexpected.
Now the industry has an opportunity to ask:
Was the command authenticated?
Could it be replayed?
Is the activation code static?
Are identical codes used in multiple jurisdictions?
Can the receiver validate the source?
Does the system log the originating signal?
Can operators distinguish a local controller from distant interference?
Are there rate limits, confirmation steps, sequence protections, or secondary validation mechanisms?
What other systems use the same signaling model?
Those are not questions that should remain confined to one county, one manufacturer, or one siren system.
Dallas showed what happens when someone deliberately reaches the pathway.
Huntington County showed that nature could reach it accidentally.
The telephone network showed us decades ago why accepting a sound as authority is dangerous.
How many times do we need to learn the same lesson?
The Lesson for the Next Generation
I have been in this industry for 45 years, and I have seen this pattern repeat.
The equipment changes.
The interfaces change.
The acronyms change.
The attack is described as new because it affects a new product, a new platform, or a new generation of infrastructure.
But beneath the surface, it is often an old weakness:
A predictable code.
A reusable command.
An unverified source.
An open input.
A trusted tone.
A system that knows what was said but has no reliable way to know who said it.
When we forget the simple security lessons, they return as modern threats.
That is why we must talk about these incidents.
Not to embarrass the people operating the systems.
Not to provide a cookbook to attackers.
Not to create panic.
We talk about them because unshared lessons disappear.
We talk about them because accidental discoveries can become deliberate exploits.
We talk about them because the next engineer designing a warning system, building-control network, emergency communications platform, or public-safety interface needs to understand that the most dangerous input may not arrive through the network being monitored.
Sometimes it arrives through the antenna.
Sometimes it arrives through the microphone.
Sometimes it sounds exactly like a legitimate command.
Silence is not golden.
Silence extends the problem.
And the newest threat in the room may be a lesson the industry learned decades ago—and then forgot.
