Juice Jacking: When Charging Your Device Opens the Door to Hackers

Rahul Sahi & Neeraj Soni
Rahul Sahi & Neeraj Soni
Policy & Advocacy, CyberPeace
PUBLISHED ON
May 22, 2025
10

Introduction

In the hyper-connected era, something as mundane as charging your phone can become a gateway to cyberattacks. A recent experience of Assam Chief Minister Himanta Biswa Sarma has reignited fears of an emerging digital menace called juice jacking. Sarma, who was taking an Emirates flight from Delhi to Dubai, used an international charger and cable provided by another passenger on board. As he afterwards reported on X (formerly Twitter), the passenger got off while he slept and so could not return the borrowed items. Though most people admired the CM's humility and openness, cybersecurity experts and citizens were quick to point out a possible red flag, that it could be a juice-jacking attempt. Whether by design or not, the scene calls out to the concealed risks of using unfamiliar charging equipment, particularly for those who hold sensitive roles.

What Is Juice Jacking?

Juice jacking takes advantage of the multi-purpose nature of USB connectors, which can carry both electrical energy and information. Attackers hack USB ports or cables to either:

  • Insert harmful payloads (malware, spyware, ransomware) during power transfer, or
  • Create unauthorised data pathways for silent information exfiltration.

Types of Juice Jacking Attacks

  1. Data Theft (Exfiltration Attack): The USB cable or port is rigged to silently extract files, media, contacts, keystrokes, or login information from the attached phone.
  2. Malware Injection (Payload Attack): The USB device is set to impersonate a Human Interface Device (HID), such as a keyboard. It sends pre-defined commands (shell scripts, command-line inputs) to the host, loading backdoors or spying tools.
  3. Firmware Tampering: In more sophisticated cases, attackers implement persistent malware at the bootloader or firmware level, bypassing antivirus protection and living through factory resets.
  4. Remote Command-and-Control Installation: Certain strains of malware initiate backdoors to enable remote access to the device over the internet upon reconnection to a live network.

Why the Assam CM’s Incident Raised Flags 

Whereas CM Sarma's experience was one of thanks, the digital repercussions of this scenario are immense:

  • High-value targets like government officials, diplomats, and corporate executives tend to have sensitive information.
  • A hacked cable can be used as a spy tool, sending information or providing remote access.
  • With the USB On-The-Go (OTG) feature in contemporary Android and iOS devices, an attacker can run autorun scripts and deploy payloads at device connect/disconnect.
  • If device encryption is poor or security settings are incorrectly configured, attackers may gain access to location, communication history, and app credentials.

Technical Juice Jacking Indicators

The following are indications that a device could have been attacked:

  • Unsolicited request for USB file access or data syncing on attaching.
  • Faster battery consumption (from background activities).
  • The device is acting strangely, launching apps or entering commands without user control.
  • Installation of new apps without authorisation.
  • Data consumption increases even if no browsing is ongoing.

CyberPeace Tech-Policy Advisory: Preventing Juice Jacking

  1. Hardware-Level Mitigation
    1. Utilise USB Data Blockers: Commonly referred to as "USB condoms," such devices plug the data pins (D+ and D-), letting only power (Vcc and GND) pass through. This blocks all data communication over USB.
    2. Charge-Only Cables: Make use of cables that physically do not have data lines. These are specifically meant to provide power only.
    3. Carry a Power Bank: Use your own power source, if possible, for charging, particularly in airports, conferences, or flights.
  1. Operating System(OS) Level Protections
  1. iOS Devices:

Enable USB Restricted Mode:

Keep USB accessories from being able to connect when your iPhone is locked.

Settings → Face ID & Passcode → USB Accessories → Off

  1. Android Devices:

Disable USB Debugging:

Debugging makes device access available for development, but it can be taken advantage of. If USB Debugging is turned on, and someone connects your phone to a computer, they might be able to access your data, install apps, or even control your phone, especially if your phone is unlocked. Hence, it should be kept off. 

Settings → Developer Options → USB Debugging → Off

  1. Set USB Default to 'Charge Only'

Settings → Connected Devices → USB Preferences → Default USB Configuration → Charge Only

3) Behavioural Recommendations

  • Never take chargers or USB cables from strangers.
  • Don't use public USB charging points, particularly at airports or coffee shops.
  • Turn full-disk encryption on on your device. It is supported by most Android and all iOS devices.
  • Deploy endpoint security software that can identify rogue USB commands and report suspicious behaviour.
  • Check cables or ports physically, many attack cables are indistinguishable from legitimate ones (e.g., O.MG cables).

Conclusion

"Juice jacking is no longer just a theoretical or obscure threat. In the age of highly mobile, USB-charged devices, physical-layer attacks are becoming increasingly common, and their targets are growing more strategic. The recent case involving the Assam Chief Minister was perhaps harmless, but it did serve to underscore a fundamental vulnerability in daily digital life. As mobile security becomes more relevant to individuals and organisations worldwide, knowing about hardware-based attacks like juice jacking is essential. Security never needs to be sacrificed for convenience, particularly when an entire digital identity might be at risk with just a single USB cable.

References

PUBLISHED ON
May 22, 2025
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