What is Iisa virus?
Iisa virus is a new ransomware that belongs to the family of ransomware called STOP (Djvu). Ransomware is a form of malware that encrypts the victim’s files and demands a ransom for decrypting them. The Iisa virus encrypts files, renames them by appending the .iisa extension, and creates files named “_readme.txt” containing the ransom demand message. For example, a file named “image.jpg” will be renamed to “image.jpg.iisa”, a “document.docx” file to “document.docx.iisa”, “invoice.pdf” to “invoice.pdf.iisa”, and so on.
Screenshot of files encrypted by Iisa virus (‘.iisa’ file extension)
QUICK LINKS
- What is Iisa virus?
- Remove Iisa virus (ransomware)
- Decrypt .iisa files
- Restore .iisa files
- Video Guide
Iisa ransomware is a new malware that encrypts files on the victim’s computer and demands a ransom payment to restore access to the contents of these files. It targets users running Microsoft Windows. In most cases, this malware requires user actions in order to be installed on the computer. Typically, criminals use various tricks, for example, disguising the malicious software as a freeware, cracks, activators and key generators, so that victims download and run Iisa virus on their computer.
Upon infecting a computer, the Iisa ransomware performs the following steps as part of its preparation for encrypting files: creates a folder in the Windows system directory and copies itself to it; adds itself to the list of programs that start up every time the computer is turned on; collects information about the victim’s computer; establishes connection with its command server (C&C).
If Iisa was able to establish a connection with the C&C server, then it sends some information about the victim’s computer to the server, and the server returns a key to it that must be used to encrypt files. Such a key is called ‘online key’ and it is unique for each case of ransomware infection. If a connection to the C&C server has not been established, the ransomware uses a fixed key (so called ‘offline key’), which is unique for each version of STOP (djvu) ransomware, but the same for each case of Iisa infection.
Having determined which key to use, Iisa ransomware virus goes to the main thing – it starts the file encryption process. Of course, it does not encrypt absolutely all files, since encryption of the Windows system files will cause the computer to stop working. Therefore, the ransomware does not encrypt files located in the system directory of Windows, as well as files with the following extensions: ‘.sys, .dll, .lnk, .ini, .bat’. In addition, Iisa virus does not encrypt files named ‘_readme.txt’. All other files will become the target of the malware, for example, the following file types can be encrypted:
.xyp, .tax, .wbm, .y, .srf, .dwg, .sidn, .js, .cdr, .mpqge, .1st, .itl, .xmind, .wgz, .menu, .crt, .wdb, .doc, .apk, .bay, .ysp, .qic, .sql, .sidd, .nrw, .wotreplay, .wbc, .wsd, .xy3, .lrf, .xlsb, .xlsx, .dmp, .psd, .wbd, .dcr, .z, .ntl, .bik, .indd, .rim, .wire, .jpe, .t13, .p7b, .pptm, .sid, .forge, .zabw, .pem, .3dm, .sr2, .x3f, .wpt, .pak, .hplg, .bc6, .dng, .odc, .m4a, .wav, .xdl, .odb, .xpm, .xll, .ff, .eps, .erf, .bar, .7z, .iwd, .crw, .jpeg, .der, .pkpass, .ptx, .3fr, .xls, .wri, .zip, .webdoc, .xyw, .xwp, .z3d, .wdp, .xlk, .slm, .flv, .vpp_pc, .pfx, .zw, .d3dbsp, .png, .itdb, .fsh, .pdf, .db0, .odm, .webp, .raw, .wp, .mddata, .upk, .xbplate, .zif, .wmv, .psk, .xlsm, .zip, .ncf, .ws, .cer, .wbmp, .map, .zdc, .wbz, .mcmeta, .sum, .lbf, .wpb, .epk, .accdb, .p12, .yal, .sis, .syncdb, .xx, .vdf, .m2, .ppt, .raf, .dba, .big, .mef, .vfs0, .xbdoc, .wpa, .0, .docx, .hkx, .cfr, .wpd, .pdd, .fos, .srw, .txt, .csv, .hvpl, .gho, .wmo, .bsa, .rw2, .avi, .wpg, .vtf, .cas, .pef, .mdb, .m3u, .x3d, .wmv, .layout, .wot, .w3x, .dxg, .mrwref, .arw, .bc7, .gdb, .lvl, wallet, .py, .wpw, .snx, .mov, .css, .ibank, .mlx, .xlsm, .xlsx, .wm, .wp7, .kf, .wcf, .jpg, .odp, .qdf, .desc, .wp4, .odt, .ztmp, .xf, .blob, .sav, .wpe, .asset, .wp5, .xld, .dbf, .vpk, .mdbackup, .arch00, .ybk, .das, .sie, .wbk, .3ds, .wpd, .zdb, .tor, .hkdb, .icxs, .x3f, .iwi, .mp4, .rgss3a, .rwl, .kdb, .rar, .wn, .cr2, .wmd, .p7c, .orf
All encrypted files become completely useless, their contents cannot be read in any way. To clearly show that the files are encrypted, the ransomware virus appends a new ‘.iisa’ extension at the end of the filename of each encrypted file. This means the following: if the file had the name ‘photo-image.jpg’, then after it has been encrypted, it will be called ‘photo-image.jpg.iisa’. In all directories where there are encrypted files, Iisa virus drops a file named ‘_readme.txt’
Screenshot of the contents of ‘_readme.txt’ file (Iisa ransom demand message)
This file contains text written by Iisa authors. In this message, the criminals report that the user’s files were encrypted and the only way to get them back is to purchase a key and a decryptor. Attackers give the victim 72 hours. At this time, the key will cost $490, after 72 hours the ransom will increase to $980. The message also contains the contact information of the criminals, using which the victim can check the ability of the attackers to decrypt .iisa files, as well as find out where to send the ransom.
Text presented in the _readme.txt file:
ATTENTION!
Don’t worry, you can return all your files!
All your files like pictures, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
https://we.tl/t-ZmofmHikRP
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that’s price for you is $490.
Please note that you’ll never restore your data without payment.
Check your e-mail “Spam” or “Junk” folder if you don’t get answer more than 6 hours.To get this software you need write on our e-mail:
manager@mailtemp.chReserve e-mail address to contact us:
helprestoremanager@airmail.ccYour personal ID:
0351xxxxxxxx
Threat Summary
| Name | Iisa ransomware, Iisa file virus |
| Type | File locker, Ransomware, Crypto malware, Crypto virus, Filecoder |
| File extension | .iisa |
| Ransom note | _readme.txt |
| Contact | manager@mailtemp.ch, helprestoremanager@airmail.cc |
| Ransom amount | $980, $490 in Bitcoins |
| Detection Names | W32.AIDetect.malware2, Win.Packed.Generic-9908949-0, HEUR:Trojan-Ransom.Win32.Stop.gen, Trojan.Malware.300983.susgen, BehavesLike.Win32.Generic.jc, ML/PE-A + Troj/Krypt-BO, Malware-Cryptor.2LA.gen, ML.Attribute.HighConfidence, Trojan.Win32.Save.a |
| Symptoms | Encrypted photos, documents and music. Your documents, photos and music have a wrong name, suffix or extension, or don’t look right when you open them. Files named like ‘_readme.txt’, ‘#_README_#’, ‘_DECRYPT_’ or ‘recover’ in each folder with at least one encrypted file.. Ransom note in a pop-up window with cybercriminal’s ransom demand and instructions. |
| Distribution ways | Unsolicited emails that are used to deliver malware. Drive-by downloads from a compromised website. Social media posts (they can be used to force users to download malicious software with a built-in ransomware downloader or click a misleading link). USB sticks containing malware. |
| Removal | Iisa ransomware removal guide |
| Decryption | Iisa File Decrypt Tool |
In file ‘_readme.txt’, criminals scare victims by saying that encrypted files cannot be decrypted without paying a ransom. And unfortunately this is true, the contents of the files cannot be read while the files are encrypted, and a key and decryptor are needed to decrypt them. Fortunately, there is a free Iisa File Decrypt Tool. This decryptor can help each victim to decrypt .iisa files for free. But in addition to the decryptor, the key is still necessary. As we reported above, the virus can use two types of keys. An offline key can be determined by researchers, but only criminals have an online key. Thus, files encrypted with so called ‘offline key’ can be decrypted. And all files that have been encrypted with so called ‘online key’ cannot yet be decrypted. In this case, the alternative methods listed below in this article can be used to recover the contents of these files.
How to remove Iisa virus (ransomware)
Before you start decrypting or recovering .iisa files, you need to remove the Iisa virus. This must be done since otherwise the ransomware may re-encrypt the restored files. You can stop the ransomware from working, as it is not difficult to do. Another option is to perform a full system scan using free malware removal tools capable of detecting and removing ransomware infection. It is very important to read the entire instruction manual carefully and make sure to understand it all. We advise you not to skip any steps, each of the steps is very important and must be completed by you. In order not to get confused and not miss an important point in the instructions, we recommend that you print this article or open it on your smartphone.
It is very important to scan the computer for malware, as security researchers found that spyware could be installed on the infected computer along with the Iisa ransomware. Spyware is a very dangerous security threat as it is designed to steal the user’s personal information such as passwords, logins, contact details, etc. If you have any difficulty removing the Iisa virus, then let us know in the comments, we will try to help you.
To remove Iisa virus, follow the steps below:
Kill Iisa virus
Press CTRL, ALT, DEL keys together.
Click Task Manager. Select the “Processes” tab, look for something suspicious that is the Iisa ransomware then right-click it and select “End Task” or “End Process” option. If your Task Manager does not open or the Windows reports “Task manager has been disabled by your administrator”, then follow the guide: How to Fix Task manager has been disabled by your administrator.
It is not difficult to detect a process related to the Iisa ransomware. When looking for a malicious process, pay attention to the process icon and its name. Most often, this ransomware has a process name in the following format: 4-characters.tmp.exe or 4-characters.exe. For example: 7533.tmp.exe, A4b1.exe, CD15.tmp.exe, 19b2.exe. The process name can also contain “(32 bit)”. If you do not find a process with a similar name in the list of processes, then most likely the Iisa ransomware has finished working. But keep in mind, if you do not remove the ransomware autostart entries, as demonstrated below, and do not delete its file, then after a while it may start again, and if it finds unencrypted files, immediately encrypt them.
Disable Iisa startup
Select the “Start-Up” tab, look for something similar to the one shown in the example below, right click to it and select Disable.
Close Task Manager.
Delete Iisa task
Type “Task Scheduler” in the search bar. Click Task Scheduler app in the search results. Click “Task Scheduler Library” in the left panel. On the right panel, right-click to “Time Trigger Task” and select Delete.
Close Task Scheduler.
Remove Iisa virus
Run Task Manager and select the “Start-Up” tab. Right click to the Iisa startup entry and select Open File Location as shown below.
A directory containing one file will open in front of you, this file is the Iisa virus. It needs to be removed. If you try to delete it immediately, then you will not succeed, since this file is protected from deletion.
To delete this file, you need to do the following. Right-click on the file, select Properties. In the window that opens, select Security tab. Next, click the Advanced button below. A window will open as shown in the following example.
Click Disable inheritance. In the Block inheritance dialog box that opens, select the first item (Convert inherited permissions…) as shown below.
In the Permission entries list, select “Deny Everyone”, click Remove button and then OK. Close the file properties window. You should now be able to remove the Iisa virus. Right-click on the file and select Delete.
Scan computer for malware
Zemana Anti-Malware is a malware removal tool that is very effective for detecting and removing ransomware. The steps below will explain how to download, install, and use Zemana to scan your computer and remove Iisa virus.
Download Zemana Anti-Malware on your Windows Desktop from the link below.
164110 downloads
Author: Zemana Ltd
Category: Security tools
Update: July 16, 2019
When the download is complete, close all software and windows on your computer. Double-click the setup file named Zemana.AntiMalware.Setup. If the “User Account Control” dialog box pops up as shown on the screen below, click the “Yes” button.
It will open the “Setup wizard” which will help you setup Zemana Anti Malware on your computer. Follow the prompts and do not make any changes to default settings.
Once install is complete successfully, Zemana will automatically start and you can see its main screen as shown in the following example.
Now press the “Scan” button to perform a system scan with this tool for the Iisa ransomware virus, other malware, worms and trojans. A system scan can take anywhere from 5 to 30 minutes, depending on your device. While the Zemana Anti-Malware is scanning, you can see number of objects it has identified as being infected by malicious software.
After the system scan is finished, it will show a list of all threats found by the scan. Review the scan results and then click “Next” button. Zemana Anti-Malware will remove Iisa virus and move the selected security threats to the program’s quarantine. When the clean up is done, you may be prompted to restart the personal computer.
In order to be 100% sure that the computer no longer has the Iisa ransomware virus, we recommend using Kaspersky virus removal tool (KVRT). It is a free removal utility that can check your PC for a wide range of security threats such as ransomware, adware, spyware, potentially unwanted software, trojans, worms as well as other malicious software. It will perform a deep scan of the system including hard drives and Windows registry. When a malicious software is found, it will help you to delete all detected threats from your computer by a simple click.
Download Kaspersky virus removal tool on your PC from the following link.
129082 downloads
Author: Kaspersky® lab
Category: Security tools
Update: March 5, 2018
When downloading is done, double-click on the Kaspersky virus removal tool icon. Once initialization process is complete, you will see the Kaspersky virus removal tool screen as shown on the image below.
Click Change Parameters and set a check near all your drives. Press OK to close the Parameters window. Next press Start scan button to perform a system scan for the Iisa virus and other trojans and harmful software. This procedure can take some time, so please be patient. While the utility is scanning, you can see how many objects and files has already scanned.
When the checking is finished, KVRT will show a list of found items such as the one below.
Review the report and then click on Continue to begin a cleaning procedure.
How to decrypt .iisa files
Files with the extension ‘.iisa’ are encrypted files. The virus uses a long key and a strong encryption algorithm, so it is impossible to decrypt files without a key and decryptor. Criminals demand a ransom for the key and the decryptor. Of course, even paying a ransom, there is no guarantee that victims will receive the required key and decryptor. Fortunately, there is a free Iisa File Decrypt Tool that allows everyone to decrypt .iisa files for free.
Iisa File Decrypt tool (STOP Djvu decryptor)
To decrypt .iisa files, use Iisa File Decrypt tool:
- Go to the following link to download Iisa File Decrypt tool.
STOP Djvu decryptor - Scroll down to ‘New Djvu ransomware’ section.
- Click the download link and save the ‘decrypt_STOPDjvu.exe’ file to your desktop.
- Run decrypt_STOPDjvu.exe, read the license terms and instructions.
- On the ‘Decryptor’ tab, using the ‘Add a folder’ button, add the directory or disk where the encrypted files are located.
- Click the ‘Decrypt’ button.
Iisa File Decrypt Tool is a free software that can decrypt the encrypted files only in some cases, when the files were encrypted with an ‘offline key’. If the files were encrypted with an ‘online key’, then they cannot be decrypted. The reason for this is that the decryption key is in the hands of criminals and this key can not be determined. This does not mean that if your files are encrypted with an online key, then their contents are lost forever. Fortunately, there are several ways to recover encrypted files. These methods do not involve the use of decryption and therefore can be used in any case, no matter what key the ransomware used to encrypt files.
How to find out which key was used to encrypt files
Below we show two ways to help you determine what type of key was used to encrypt your files. This is very important, since the type of key determines whether it is possible to decrypt .iisa files. We recommend using the second method, as it is more accurate.
Personal ID is highlighted here
Find out the type of key using ‘_readme.txt’ file
- Open the ransom demand message (‘_readme.txt’ file).
- Scroll down to the end of the file.
- There you will see a line with the text ‘Your personal ID’.
- Below is a line of characters – this is your personal id.
Find out the type of key using ‘PersonalID.txt’ file
- Open disk C.
- Open directory ‘SystemID’.
- Open file named ‘PersonalID.txt’. This file lists ‘Personal ID’s that match the keys that the Iisa ransomware used to encrypt files.
The ‘Personal ID’ is not a key, it is an identifier related to a key that was used to encrypt files. If the ID ends with ‘t1’, then the files are encrypted with an offline key. If the ID does not end with ‘t1’, Iisa ransomware virus used an online key. If you could not figure out how to determine which key was used to encrypt files, then we can help. Just write a request here or in the comments below.
Iisa File Decrypt Tool : “No key for New Variant online ID”
If, when you try to decrypt .iisa files, Iisa File Decrypt Tool reports:
No key for New Variant online ID: *
Notice: this ID appears to be an online ID, decryption is impossible
It means that your files are encrypted with an ‘online key’ and their decryption is impossible, since only the Iisa authors have the key necessary for decryption. In this case, you need to use alternative methods listed below to restore the contents of encrypted files.
Iisa File Decrypt Tool : “No key for New Variant offline ID”
If, during decryption of .iisa files, Iisa File Decrypt Tool reports:
No key for New Variant offline ID: *t1
Notice: this ID appears be an offline ID, decryption MAY be possible in the future.
It means the following: your files are encrypted with an ‘offline key’, but the key itself has not yet been obtained by security researchers, in this case, you need to be patient and wait a while, in addition, you can also use alternative ways for recovering encrypted data.
If for some reason you were unable to decrypt the encrypted files, then We recommend to follow the news on our Facebook or YouTube channels. So you ‘ll know right away that it ‘s possible to decrypt .iisa files.
This video step-by-step guide will demonstrate How to use remove Iisa virus, Decrypt/Recover .iisa files.
How to restore .iisa files
If the Iisa File Decrypt tool cannot decrypt the encrypted files or your data is encrypted with an online key, then there is no need to despair. Fortunately, there are several alternative methods that can allow everyone to recover the contents of encrypted files. Each of these methods does not involve the use of special knowledge and paid programs and can be performed by everyone. We have prepared an instruction with illustrations, which describes in detail the process of data recovery. Before you begin data recovery, if you have not completed step 1, then go back. You must be 100% sure that Iisa ransomware virus is completely removed. We recommend using free malware removal tools.
Use ShadowExplorer to recover .iisa files
The first and very simple way to restore encrypted files to the state in which they were before encryption is to restore files from their Shadow Copies. The Shadow Volume Copies are copies of files and folders that Windows automatically saved as part of system protection. This feature is fantastic at rescuing personal files that were locked by Iisa ransomware. The guide below will give you all the details.
Visit the following page to download ShadowExplorer. Save it on your Windows desktop or in any other place.
438817 downloads
Author: ShadowExplorer.com
Category: Security tools
Update: September 15, 2019
Once the downloading process is done, open a directory in which you saved it. Right click to ShadowExplorer-0.9-portable and select Extract all. Follow the prompts. Next please open the ShadowExplorerPortable folder as shown on the screen below.
Double click ShadowExplorerPortable to run it. You will see the a window as shown in the figure below.
In top left corner, select a Drive where encrypted personal files are stored and a latest restore point as shown in the following example (1 – drive, 2 – restore point).
On right panel look for a file that you wish to recover, right click to it and select Export as displayed below.
This video step-by-step guide will demonstrate How to recover encrypted files using Shadow Explorer.
Restore .iisa files with PhotoRec
Another way to recover encrypted files is to use data recovery programs. There are many such programs, but most of them are paid. We recommend using a program called PhotoRec. It has all the necessary functions and is completely free.
Download PhotoRec by clicking on the following link. Save it directly to your Microsoft Windows Desktop.
When the download is finished, open a directory in which you saved it. Right click to testdisk-7.0.win and select Extract all. Follow the prompts. Next please open the testdisk-7.0 folder as displayed on the image below.
Double click on qphotorec_win to run PhotoRec for Windows. It will show a screen as shown in the following example.
Choose a drive to recover as shown on the screen below.
You will see a list of available partitions. Choose a partition that holds encrypted personal files as displayed on the image below.
Click File Formats button and select file types to restore. You can to enable or disable the recovery of certain file types. When this is complete, click OK button.
Next, press Browse button to choose where restored personal files should be written, then press Search. We strongly recommend that you save the recovered files to an external drive.
Count of restored files is updated in real time. All restored personal files are written in a folder that you have chosen on the previous step. You can to access the files even if the recovery process is not finished.
When the restore is finished, click on Quit button. Next, open the directory where restored documents, photos and music are stored. You will see a contents as shown in the figure below.
All restored photos, documents and music are written in recup_dir.1, recup_dir.2 … sub-directories. If you’re looking for a specific file, then you can to sort your restored files by extension and/or date/time.
This video step-by-step guide will demonstrate How to recover encrypted files using PhotoRec.
How to protect your PC from Iisa ransomware
Most antivirus apps already have built-in protection system against the crypto virus. Therefore, if your machine does not have an antivirus program, make sure you install it. As an extra protection, use the HitmanPro.Alert. HitmanPro.Alert is a small security tool. It can check the system integrity and alerts you when critical system functions are affected by malware. HitmanPro.Alert can detect, remove, and reverse ransomware effects.
Please go to the link below to download HitmanPro.Alert. Save it to your Desktop so that you can access the file easily.
When the downloading process is finished, open the file location. You will see an icon like below.
Double click the HitmanPro Alert desktop icon. When the utility is opened, you will be shown a window where you can select a level of protection, as displayed in the figure below.
Now press the Install button to activate the protection.
Finish words
This article was created to help all victims of the Iisa ransomware virus. We tried to give answers to the following questions: how to remove ransomware; how to decrypt .iisa files; how to recover encrypted files; what is an online key and what is an offline key. We hope that the information presented in this article has helped you.
If you have questions, then write to us, leaving a comment below. If you need more help with Iisa ransomware related issues, go to here.
This is the key
0351gSd743dfB8P5WJQejYcA5XSCRIa5tncIpUqNqKFRpsqDrm9
The “0345uSifkeybsFqlzHqnbKSKaodilWTiSUHkHewT7xF41SzWwH” ID is related to an online key, so files cannot be decrypted. Try to restore the contents of encrypted files using ShadowExplorer and PhotoRec.