Unwanted Location Tracking

Unwanted location tracking is the use of Bluetooth item trackers — Apple AirTag, Tile, Samsung and Google Find My accessories — to follow a person without consent. The devices are built to find lost property: the tag broadcasts Bluetooth LE advertisements, phones belonging to other users of the finder network report sightings to a central service, and the owner sees where the tag was last observed. A tag slipped into a bag, coat, or car turns that same crowdsourced machinery into a stalking tool, with coverage far beyond any single stalker’s reach. ¹

Detecting Unwanted Location Trackers (DULT) is the IETF working group standardizing how tags, non-owner devices, and finder networks behave so the misuse is discoverable across platforms. Its drafts and the industry events around them are the best-documented account of the problem’s shape.

How the tracking works

A separated tag advertises over Bluetooth LE; the finder network aggregates reports from bystanders’ phones. The tag’s public address rotates to protect owner privacy — the DULT accessory protocol requires rotation every 15 minutes in near-owner mode and every 24 hours when separated, which keeps a stable identifier alive long enough for a non-owner’s detection algorithm to establish persistence. A near-owner bit in the advertisement tells nearby devices to suppress alerts while the owner is present. ² The rotation scheme is an application of the same privacy property as MAC address randomization, and it carries the same limits — see mac-address.

Mitigation layers

Separation sound. A tag away from its owner emits a chirp when moved. Apple’s first implementation did not fire until the tag had been out of range of its owner’s phone for three days, and the beep was easy to muffle; Apple shortened the delay, and the second-generation AirTag made the speaker harder to remove. ³

Platform tracking alerts. iOS and iPadOS notify a user when an unknown tag travels with them (“AirTag Found Moving With You”, with a map of sightings); iOS 14.5 covered Find My accessories and iOS 17.5 extended detection to compatible third-party tags under the Apple/Google joint specification, rolled out to Android 6.0+ in May 2024. The alert flow offers Play Sound, Precision Finding over Ultra Wideband, NFC identification of the tag, and “Instructions to Disable”; law enforcement can request owner information from Apple. Disabling Bluetooth or Find My on the target’s own device does not stop the owner seeing the tag — only disabling the tag itself does. ⁴

Cross-platform standardization. The DULT accessory protocol specifies the recognizable advertisement payload (network ID, near-owner bit, proprietary company payload), non-owner controls (play sound, identifier retrieval over Bluetooth LE, NFC, or server), a sound maker and motion detector on the tag, disablement instructions, and an owner registry that stores obfuscated owner information for law-enforcement retrieval. Platforms are expected to detect and exclude nonconformant tags from finder networks. ⁵

The Silencer episode (September–October 2026)

On September 30, 2026, ElevationLab — a long-time AirTag accessory maker — announced the “Silencer” for $9.99: a pin positioned over the AirTag’s speaker, struck with a hammer to puncture the casing and destroy the speaker without damaging the rest of the hardware. Its stated purpose was anti-theft: a thief would not hear the tracker on a stolen bike. Glenn Fleishman attacked the product in Six Colors on October 1; EFF’s Eva Galperin criticized it for putting property recovery ahead of people’s safety. Around October 13, ElevationLab pulled the product and published a note titled “An apology”: “In retrospect though, this also has the side effect of aiding someone with bad intentions to track someone that wouldn’t get phone notifications.” The company said it would use its patent on the tool to prevent anyone else making one. ⁶

Safety features are dual-use

EFF’s 2023 position states the design constraint flatly: “It is impossible to make an anti-theft device that does not alert the thief that they are being tracked without also making a perfect tool for stalking.” The audible chirp exists because silent tracking is the harm; muting it converts the safeguard into a stealth tracker. The Silencer is the physical case of a general pattern. The software case is Tile’s “Anti-Theft” mode, which suppresses tracking alerts for verified owners: the DULT threat model calls this out as plainly failing the recommendation that tracking alerts should not be circumventable, because ID verification only helps if the tracked person finds the physical item — the exact event the mode is designed to prevent. ^{7 8}

Threat model highlights

The DULT threat model builds its persona taxonomy on the MAP framework: attackers vary by expertise, proximity to the target (household access being the modal case), and resources; targets vary by expertise, whether they suspect tracking at all, and whether they can safely use safeguards like scanning apps. Tag placement changes the attack — on the person gives fine-grained tracking; in a child’s backpack or a car is coarser and less likely to be recognized; multiple tags in mixed placements lead a target to believe the problem is solved when it is not. ⁹

Attacks on the detection machinery itself include: deploying multiple tags; physically modifying tags (disabling the speaker or shielding the antenna — rated medium risk, needing moderate skill plus physical access, with speaker-impedance monitoring only a partial counter); firmware modification (the protocol requires authenticated firmware images, but a bypassed tag can thin out its advertisements or churn identifiers); and remote advertisement monitoring, where signal fingerprinting and RSSI correlation defeat rotating identifiers — demonstrated by Eldridge et al. and the deTagtive work. Detection requirements therefore include passive heuristics (duration of proximity, movement correlation, signal-strength trends, persistence, hardware identity) rather than relying on any single signal. ¹⁰

Open questions

• Identifier rotation versus correlation research: 24-hour stable separation-mode identifiers are exactly the window de-anonymization techniques exploit, and EFF flagged the rotation interval as too slow against a sophisticated network. ¹¹
• Patent posture: Apple filed IPR disclosures claiming patents over the DULT specification; EFF argues privacy-protecting detection technology should be free to implement. ElevationLab’s Silencer patent pledge is the mirror-image question — a defensive patent used to suppress a safety-adjacent accessory. ¹²
• Circumventable alerts: any “anti-theft mode” or accessory that suppresses detection conflicts with DULT’s core recommendation. Where the line sits is a product-policy question the standard cannot enforce alone.

Connections

• transparent-society — Brin’s wager that surveillance tech is cheap and unstoppable, answered by reciprocity: DULT is a reciprocity mechanism for trackers, making the watcher’s hardware detectable by the watched.
• conference-device-security — hidden trackers in belongings as a physical-security assessment item; knowing what hardware travels with you is the same discipline as knowing what hardware enters a conference.
• moscow-rules — counter-surveillance awareness in the physical world; the multi-tag placement attack is a direct reason a single sweep can end too early.
• ledger-nanox-spy-implant-2026 — the other 2026 hidden-tracking-hardware case: a covert device that passes its own checks, where the safety feature (attestation, chirp) is the thing being subverted.
• mac-address — BLE address rotation as a privacy mechanism and its correlation limits.

Sources

• Marcus Mendes 2026 — ElevationLab pulls AirTag Silencer after backlash over stalking concerns
• Alexis Hancock, Eva Galperin 2023 — The Industry Discussion About Standards For Bluetooth-Enabled Physical Trackers Is Finally Getting Started
• Apple 2026 — What to do if you get an alert that an AirTag, set of AirPods, Find My network accessory, or compatible Bluetooth location-tracking device is with you
• M. Delano, J. Lowell, S. Prabhu 2026 — DULT Threat Model
• B. Ledvina, D. Lazarov, B. Detwiler, S. P. Polatkan 2024 — Detecting Unwanted Location Trackers Accessory Protocol

Footnotes

1. M. Delano, J. Lowell, S. Prabhu 2026 — DULT Threat Model ↩

2. B. Ledvina, D. Lazarov, B. Detwiler, S. P. Polatkan 2024 — Detecting Unwanted Location Trackers Accessory Protocol ↩

3. Alexis Hancock, Eva Galperin 2023 — The Industry Discussion About Standards For Bluetooth-Enabled Physical Trackers Is Finally Getting Started ↩

4. Apple 2026 — What to do if you get an alert that an AirTag, set of AirPods, Find My network accessory, or compatible Bluetooth location-tracking device is with you ↩

5. B. Ledvina, D. Lazarov, B. Detwiler, S. P. Polatkan 2024 — Detecting Unwanted Location Trackers Accessory Protocol ↩

6. Marcus Mendes 2026 — ElevationLab pulls AirTag Silencer after backlash over stalking concerns ↩

7. Alexis Hancock, Eva Galperin 2023 — The Industry Discussion About Standards For Bluetooth-Enabled Physical Trackers Is Finally Getting Started ↩

8. M. Delano, J. Lowell, S. Prabhu 2026 — DULT Threat Model ↩

9. M. Delano, J. Lowell, S. Prabhu 2026 — DULT Threat Model ↩

10. M. Delano, J. Lowell, S. Prabhu 2026 — DULT Threat Model ↩

11. Alexis Hancock, Eva Galperin 2023 — The Industry Discussion About Standards For Bluetooth-Enabled Physical Trackers Is Finally Getting Started ↩

12. Alexis Hancock, Eva Galperin 2023 — The Industry Discussion About Standards For Bluetooth-Enabled Physical Trackers Is Finally Getting Started ↩