{ "id": "6161b471-e590-4f19-a0cc-556b5c2f6236", "created_at": "2026-04-06T00:07:48.236254Z", "updated_at": "2026-04-10T03:30:33.548322Z", "deleted_at": null, "sha1_hash": "a72923802b38f6c33a7af52964867c8acec80442", "title": "DoubleLocker: Innovative Android Ransomware", "llm_title": "", "authors": "", "file_creation_date": "0001-01-01T00:00:00Z", "file_modification_date": "0001-01-01T00:00:00Z", "file_size": 1016917, "plain_text": "DoubleLocker: Innovative Android Ransomware\r\nBy ESET Research\r\nArchived: 2026-04-05 23:09:28 UTC\r\nESET Research\r\nMobile Security\r\nDoubleLocker can change the device’s PIN, preventing victims from accessing their devices, and also encrypts the\r\ndata it finds in them - a combination that has not been seen previously in the Android ecosystem.\r\n13 Oct 2017  •  , 3 min. read\r\nESET researchers have spotted the first-ever ransomware misusing Android accessibility services. On top of\r\nencrypting data, it also locks the device.\r\nDetected by ESET products as Android/DoubleLocker.A, the ransomware is based on the foundations of a\r\nparticular banking Trojan, known for misusing accessibility services of the Android operating system. However,\r\nDoubleLocker doesn’t have the functions related to harvesting users’ banking credentials and wiping out their\r\naccounts. Instead, it has received two powerful tools for extorting money from its victims.\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 1 of 6\n\nDoubleLocker can change the device’s PIN, preventing victims from accessing their devices, and also encrypts the\r\ndata it finds in them - a combination that has not been seen previously in the Android ecosystem.\r\n“Given its banking malware roots, DoubleLocker may well be turned into what could be called ransom-bankers.\r\nTwo-stage malware that first tries to wipe your bank or PayPal account and subsequently locks your device and\r\ndata to request a ransom… Speculation aside, we spotted a test version of such a ransom-banker in the wild as\r\nlong ago as May, 2017,” comments Lukáš Štefanko, the ESET malware researcher who discovered DoubleLocker.\r\nDistribution\r\nDoubleLocker spreads in the very same way as its banking parent does. It is distributed mostly as a fake Adobe\r\nFlash Player through compromised websites.\r\nOnce launched, the app requests activation of the malware’s accessibility service, named “Google Play Service”.\r\nAfter the malware obtains the accessibility permissions, it uses them to activate device administrator rights and set\r\nitself as the default Home application, in both cases without the user’s consent.\r\n“Setting itself as a default home app – a launcher – is a trick that improves the malware’s persistence. Whenever\r\nthe user clicks on the home button, the ransomware gets activated and the device gets locked again. Thanks to\r\nusing the accessibility service, the user doesn’t know that they launch malware by hitting Home,” explains\r\nŠtefanko.\r\nLocking both device and data\r\nDoubleLocker, once executed on the device, creates two reasons for the victims to pay.\r\nFirst, it changes the device’s PIN, effectively blocking the victim from using it.  The new PIN is set to a random\r\nvalue which the attackes neither store nor send anywhere, so it’s impossible for the user or a security expert to\r\nrecover it. After the ransom is paid, the attacker can remotely reset the PIN and unlock the device.\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 2 of 6\n\nSecond, DoubleLocker encrypts all files from the device’s primary storage directory. It utilizes the AES\r\nencryption algorithm, appending the extension “.cryeye”. “The encryption is implemented properly, which means\r\nthat, unfortunately, there is no way to recover the files without receiving the encryption key from the attackers,”\r\nsays Štefanko.\r\nThe ransom has been set to 0.0130 BTC (approximately USD 54 at time of writing) and the message highlights\r\nthat it must be paid within 24 hours. However, if the ransom is not paid, the data will remain encrypted and will\r\nnot be deleted.\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 3 of 6\n\nFigure 1: Encrypted files on a device compromised by with DoubleLocker\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 4 of 6\n\nFigure 2: A part of the DoubleLocker ransom message\r\nHow to get rid of it?\r\nIn the ransom note, the user is warned against removing or otherwise blocking DoubleLocker: “Without [the\r\nsoftware], you will never be able to get your original files back”.\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 5 of 6\n\nTo prevent unwanted removal of the “software”, the crooks even recommend disabling the user’s antivirus\r\nsoftware.\r\n“Such advice is irrelevant: all those with a quality security solution installed on their devices are safe from\r\nDoubleLocker,” explains Štefanko.\r\nThe only viable option to clean the device of the DoubleLocker ransomware is via a factory reset.\r\nFor rooted devices, however, there is a method to get past the PIN lock without a factory reset. For the method to\r\nwork, the device needed to be in the debugging mode before the ransomware got activated.\r\nIf this condition is met, then the user can connect to the device by ADB and remove the system file where the PIN\r\nis stored by Android. This operation unlocks the screen so that the user can access their device. Then, working in\r\nsafe mode, the user can deactivate device administrator rights for the malware and uninstall it. In some cases, a\r\ndevice reboot is needed.\r\nAs for the data stored on the device, there is no way to recover it, as mentioned earlier.\r\n“DoubleLocker serves as just another reason for mobile users to have a quality security solution installed, and to\r\nback up their data on a regular basis,” concludes Štefanko.\r\nHash:\r\n01d962f809ae061d1895cf71db9eeb07900929b8\r\nLet us keep you\r\nup to date\r\nSign up for our newsletters\r\nSource: https://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nhttps://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/\r\nPage 6 of 6", "extraction_quality": 1, "language": "EN", "sources": [ "Malpedia" ], "references": [ "https://www.welivesecurity.com/2017/10/13/doublelocker-innovative-android-malware/" ], "report_names": [ "doublelocker-innovative-android-malware" ], "threat_actors": [ { "id": "75108fc1-7f6a-450e-b024-10284f3f62bb", "created_at": "2024-11-01T02:00:52.756877Z", "updated_at": "2026-04-10T02:00:05.273746Z", "deleted_at": null, "main_name": "Play", "aliases": null, "source_name": "MITRE:Play", "tools": [ "Nltest", "AdFind", "PsExec", "Wevtutil", "Cobalt Strike", "Playcrypt", "Mimikatz" ], "source_id": "MITRE", "reports": null } ], "ts_created_at": 1775434068, "ts_updated_at": 1775791833, "ts_creation_date": 0, "ts_modification_date": 0, "files": { "pdf": "https://archive.orkl.eu/a72923802b38f6c33a7af52964867c8acec80442.pdf", "text": "https://archive.orkl.eu/a72923802b38f6c33a7af52964867c8acec80442.txt", "img": "https://archive.orkl.eu/a72923802b38f6c33a7af52964867c8acec80442.jpg" } }