iOS Pasteboard

Data sharing within and across applications on iOS devices is facilitated by UIPasteboard, which has two primary categories:^[1][4]

Systemwide general pasteboard: This is used for sharing data with any application and is designed to persist data across device restarts and app uninstallations, a feature that has been available since iOS 10.
Custom / Named pasteboards: These are specifically for data sharing within an app or with another app that shares the same team ID, and are not designed to persist beyond the life of the application process that creates them, following changes introduced in iOS 10.

Security considerations play a significant role when utilizing pasteboards. For instance:^[1][2]

Starting in iOS 16, directly reading a value placed on the general pasteboard by another app requires the system to confirm user intent. A programmatic value read can therefore produce an approval prompt, whereas the edit menu, keyboard shortcut, or a visibly displayed and tapped UIPasteControl represents explicit paste intent.^[5][6]
To mitigate the risk of unauthorized background monitoring of the pasteboard, access is restricted to when the application is in the foreground (since iOS 9).
The use of persistent named pasteboards is discouraged in favor of shared containers due to privacy concerns.
The Universal Clipboard feature introduced with iOS 10, allowing content to be shared across devices via the general pasteboard, can be managed by developers to set data expiration and disable automatic content transfer.

Ensuring that sensitive information is not inadvertently stored on the global pasteboard is crucial. Additionally, applications should be designed to prevent the misuse of global pasteboard data for unintended actions, and developers are encouraged to implement measures to prevent copying of sensitive information to the clipboard.^[2]

Privacy-aware attack surface (iOS 16+)

A paste prompt is both a protection and a useful test signal. Copy a unique, non-sensitive canary in a separate app, cold-start the target, and do not invoke any paste UI. A prompt at launch, resume, or view presentation indicates that the target attempted a programmatic value read. Repeat the flow while denying and allowing access, and correlate it with hooked selectors and network traffic to determine whether the app gates the read correctly or tries to upload the value. Finally, compare this with an explicit paste through the edit menu or UIPasteControl; this separates expected user-driven behavior from automatic clipboard harvesting.^[3][6]

Do not confuse classification with content access. detectPatterns(for:) / detectedPatterns(for:) can disclose that an item resembles a URL, number, email address, phone number, postal address, tracking number, or other supported pattern without returning its value and without notifying the user. This is still a small metadata oracle worth recording during an assessment. Conversely, detectValues(for:) / detectedValues(for:) returns matched values and must be treated as a content read. Hook both API families to discover apps that first classify the pasteboard and only read it when a desired pattern matches.^[4][7]

For sensitive writes, inspect whether the application supplies both UIPasteboard.OptionsKey.localOnly and expirationDate. localOnly keeps the item out of Handoff/Universal Clipboard, while expirationDate asks the system to remove it after a bounded interval. Their absence does not prove exploitability, but it increases the exposure window and number of reachable devices.^[4]

import UniformTypeIdentifiers

UIPasteboard.general.setItems(
  [[UTType.utf8PlainText.identifier: token]],
  options: [
    .localOnly: true,
    .expirationDate: Date().addingTimeInterval(60)
  ]
)

Static Analysis

For static analysis, search the source code or binary for:^[3][4]

generalPasteboard to identify usage of the systemwide general pasteboard.
Value getters such as string, strings, URL, URLs, image, images, items, itemProviders, and dataForPasteboardType:. Prioritize reads reachable from application launch, scene activation, or view-loading callbacks.
Writers such as setString:, setValue:forPasteboardType:, setItems:options:, and setItemProviders:localOnly:expirationDate:. Trace whether secrets, session material, password-reset links, OTPs, or payment data can reach them.
detectPatterns, detectedPatterns, detectValues, and detectedValues to distinguish metadata checks from value extraction.
UIPasteControl and UIPasteConfiguration to identify intended user-mediated paste flows.
pasteboardWithName:create: and pasteboardWithUniqueName for creating custom pasteboards. Verify if persistence is enabled, though this is deprecated.

Dynamic Analysis

Dynamic analysis involves hooking or tracing specific methods:^[3]

Monitor generalPasteboard for system-wide usage.
Trace pasteboardWithName:create: and pasteboardWithUniqueName for custom implementations.
Observe deprecated setPersistent: method calls to check for persistence settings.
Hook getters and their return values separately from setters and their arguments. This identifies whether the target is a clipboard source, sink, or both, without relying only on periodic polling.
Exercise multiple pasteboard representations in the same item. An app may validate the string representation but consume a URL, rich-text, image, or custom UTI representation through another code path.

Key details to monitor include:

Pasteboard names and contents (for instance, checking for strings, URLs, images).
Number of items and data types present, leveraging standard and custom data type checks.
Expiry and local-only options by inspecting the setItems:options: method.
Call timing and stack traces, especially reads performed on launch, foreground transitions, or before any visible paste action.
Outbound requests immediately after a canary is read, which can demonstrate exfiltration rather than merely local feature detection.

An example of monitoring tool usage is objection’s pasteboard monitor, which polls the generalPasteboard every 5 seconds for changes and outputs the new data. On iOS 16 and later this is an active read, not a transparent observer: injected polling executes in the target process and can itself trigger or alter paste-approval behavior. First capture the application’s own UIPasteboard calls with hooks, then use polling in a separate run so that the monitor is not mistaken for application behavior.^[3][6]

Here’s a simple JavaScript script example, inspired by the objection’s approach, to read and log changes from the pasteboard every 5 seconds:

const UIPasteboard = ObjC.classes.UIPasteboard
const Pasteboard = UIPasteboard.generalPasteboard()
var items = ""
var count = Pasteboard.changeCount().toString()

setInterval(function () {
  const currentCount = Pasteboard.changeCount().toString()
  const currentItems = Pasteboard.items().toString()

  if (currentCount === count) {
    return
  }

  items = currentItems
  count = currentCount

  console.log(
    "[* Pasteboard changed] count: " +
      count +
      " hasStrings: " +
      Pasteboard.hasStrings().toString() +
      " hasURLs: " +
      Pasteboard.hasURLs().toString() +
      " hasImages: " +
      Pasteboard.hasImages().toString()
  )
  console.log(items)
}, 1000 * 5)

iOS Pasteboard

Privacy-aware attack surface (iOS 16+)

Static Analysis

Dynamic Analysis

References