DriedSister Virus – How to Remove & Restore .下物妹! Extension Files

DriedSister Virus – How to Remove & Restore .下物妹! Extension Files

This article has been created in order to help you by explaining how to remove DriedSister virus virus from your computer system and how to restore .下物妹! encrypted files.

Security experts discovered a dangerous new malware threat called the DriedSister virus. At the moment the virus employs only a limited number of attack techniques however future updates are expected.

Threat Summary

TypeRansomware, Cryptovirus
Short DescriptionThe DriedSister virus is an original threat that can cause a lot of damage to the victim machines. The virus can impact all components of the operating system.
SymptomsThe victims may perceive performance issues and find that their data is renamed with the .下物妹! file type extension.
Distribution MethodSpam Emails, Email Attachments, Executable files
Detection Tool See If Your System Has Been Affected by DriedSister


Malware Removal Tool

User ExperienceJoin Our Forum to Discuss DriedSister.
Data Recovery ToolWindows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

DriedSister virus – Infection Process

The DriedSister virus can be distributed using different strategies. Depending on the specific attack campaign the hackers can utilize various mechanisms that can be customized in order to maximize the infection ratio. Usually the most popular way is to coordinate email spam messages that include social engineering elements. The hackers distribute these messages in order to convince the users into interacting with a malicious element that leads to the virus DriedSister virus infection.

The emails themselves can be contain file attachments that lead to the infections once they are executed. In certain situations they can be placed in archives protected by passwords, the required strings can be placed in the body contents. The hackers can also combine this with hyperlinks that link to offsite hosted instances. In the last few years two specific delivery mechanisms have become popular.

The first one involves the distribution of malware software installers that represent hacker-modified instances of popular software. They can be trial or free versions that are familiar to most computer users. The criminals download the legitimate files from the official vendor sites which are then modified to include the malware code. They are then attached or linked in the email messages. Another virus distribution mechanism relies on infected documents that can made in various types: rich text documents, spreadsheets and presentations. As soon as they are opened a notification prompt appears which asks the users to enable the built-in scripts. If this is done the malware infection is launched.

Browser hijackers can deliver the DriedSister virus as part of their behavior patterns. They represent malware browser plugins that seek to redirect the users to a hacker-controlled site. This is done by changing important settings of the most popular web browsers. Usually such threats are made compatible with Mozilla Firefox, Google Chrome, Internet Explorer, Safari, Opera and Microsoft Edge. Malware payloads can also be distributed on hacker-controlled sites and file sharing networks such as BitTorrent.

DriedSister virus – Analysis and Activity

The DriedSister virus is distributed using a variety of different mechanisms. At the moment email messages remain one of them most popular tactics. They make use of malware attachments that pose as useful software or files of user interest. The criminals make use of clever social engineering tactics in order to manipulate the recipients into interacting with the malware element. The other tactic is to use hyperlinks that link to offsite hosted instances. Usually the links lead to malware controlled sites or to the virus DriedSister virus samples themselves.

In connection with this two particular case scenarios have been identified. The first one is the use of malware software installers that lead to the DriedSister virus infection. These type of files are made by taking the legitimate software installers from their official sources (usually the vendor official site) and modifying them to include the malware code. They are then uploaded to hacker-controlled sites and emails such as this one. In some cases the victims may be able to avoid installation by unchecking certain options during the installation process.

The criminals can also use infected documents that mask as files of interest: invoices, letters, notifications and etc. They can be of different types: rich text documents, spreadsheets and presentations. Once the files are opened by the victims a notification prompt appears which asks them to enable the built-in macros. If this is done the virus infection follows. The criminals can also set up appropriate scam sites such as download portals that impersonate legitimate and popular web services. The hackers can also make use of redirects and banners to distribute the malware samples.

In certain situations the DriedSister virus files can be distributed through browser hijackers. They are malware browser plugins that are intent into changing the default settings of the web browser to point to a hacker-controlled site. During the initial infection malware infections can be caused, including the DriedSister virus. Such threats are usually made compatible with the most popular software: Google Chrome, Internet Explorer, Safari, Microsoft Edge, Mozilla Firefox and Opera.

DriedSister virus – Encryption Process

The DriedSister virus does not appear to be a descendant of any of the famous malware families. The security analysis shows that it is based on a framework that allows the code to be updated further. Future versions can include stealth protection techniques that can guard it against removal. This is effective against anti-virus products, sandboxes, debuggers or virtual machines. In certain situations the malware can be programmed into deleting itself if it is unable to bypass the security products to avoid detection.

If operating system changes are introduces they can impact the Windows registry which in turn can cause application or system failure, as well as severe performance issues. The compromised system can also be instituted with a code that connects the victim computer to a command and control (C&C) server. This enables the hacker operates to spy on the users in real time as well as take over control of the machines in real time. In certain attack scenarios the hackers can manipulate the Internet connectivity options to redirect the traffic through a hacker proxy. This enables the criminals to directly intercept all network-related activity. This is also useful in man-in-the-middle attacks.

When all components have executed correctly and in the prescribed order the ransomware engine is started. At the moment the files can be recovered easily by using a quality ant-spyware solution due to the weak cipher. We expect that future versions might enforce a stronger protection. Like other similar threats it uses a built-in list of target file type extensions: images, music, videos, backups, archives, databases, documents and etc. All processed data is renamed with the .下物妹! extension. The following ransomware note message is displayed in an application instance:

こんにちは!私はあなたが命じた身代 金のウイ」以です。


A machine-translated version of it reads the following:

Dried sister! Ransom virus
Hello! I am the ice of a ransom you ordered. ”
The document has been decrypted by me.

How to Remove DriedSister virus and Restore .下物妹! Encrypted Files

In order to make sure that this malware is permanently gone from your computer, you should follow the manual or automatic removal instructions down below. If you have the experience in removing ransomware manually, we advise you to focus on the first 2 steps from the manual removal and to look for the registry files which we have explained in the analysis part above. Otherwise, if you want a more automatic and faster solution and lack the expertise in malware removal, we urge you to download an advanced anti-malware program, which aims to automatically perform the removal operation of DriedSister ransomware and secures your computer against future infections in real-time.

If you want to restore files that have been encrypted by this ransomware infection, we advise you to try out the alternative tools for file recovery down below in step “2. Restore files encrypted by .下物妹! Files Virus”. They may not guarantee fully that you will recover all of the files, but if you haven’t reinstalled your OS already, there is a good chance that you might just restore them.

Martin Beltov

Martin graduated with a degree in Publishing from Sofia University. As a cyber security enthusiast he enjoys writing about the latest threats and mechanisms of intrusion.

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