Security by antiquity can make some older technologies harder targets for hackers, although experts still recommend keeping software fully updated for most everyday use.
Finnish cybersecurity expert Mikko Hyppönen used the term after continuing to use the obsolete Eudora email application long after mainstream users had moved elsewhere.
Hyppönen said criminals usually focus on widely deployed systems because those targets offer greater financial returns. As a result, rarely used technology may attract less attention.
Computer scientist Matt Bishop saw a similar effect during cybersecurity experiments at the University of California, Davis. An older software system used as a honeypot attracted few attacks. A newer version drew substantially more. The principle also extends beyond software.
The Irish Aviation Authority has retained ground-based radio navigation beacons as part of its resilience strategy. Satellite-based Global Positioning System signals have been subjected to increased electronic jamming.
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Thomas Withington of the Royal United Services Institute said forces in Ukraine also use paper maps and compasses because adversaries cannot electronically jam them.
Meanwhile, magnetic tape remains important for offline data backups. Hugues Meyrath, chief executive of storage company Quantum, said ransomware helped sustain demand for tape during the past 10 to 15 years.
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Organisations can physically disconnect tape from computer networks, reducing its exposure to online attacks.
However, Hyppönen stressed that obsolete technology is not automatically secure. Old systems can still contain known vulnerabilities.
Experts cited in the source therefore continue to recommend current, patched technology for routine use while retaining selected legacy systems where resilience offers a specific advantage.