Removal instructions for the PdfKnight unwanted application
Written by Tomas Meskauskas on
What kind of application is PdfKnight?
Our research team discovered the PdfKnight PUA (Potentially Unwanted Application) while inspecting suspicious websites. According to the webpage promoting this app, it supposedly operates as a file format converter that can convert PDFs to Doc format documents.
Our analysis revealed that PdfKnight endorses (via redirects) the portal.pdfknight.com fake search engine. It is worth noting that PUAs often infiltrate systems bundled (i.e., together) with other unreliable and hazardous software.
PdfKnight application overview
Potentially unwanted apps commonly have undesirable and harmful abilities. When we installed PdfKnight on our testing system, it created a shortcut on the desktop. Once this file is accessed, it launches the default browser with portal.pdfknight.com opened.
This website is a fake search engine; like most pages of this kind, it cannot provide search results. Hence, portal.pdfknight.com redirects either to Yahoo (search.yahoo.com) or nearbyme.io. Note that this site could land elsewhere, as they might influenced by factors like user geolocation.
Nearbyme.io is also a fake search engine, but it can provide search results that are inaccurate and may include sponsored, deceptive, and possibly malicious content.
These fraudulent websites are typically promoted by browser hijackers that make changes to browser settings for this purpose (e.g., default search engines, homepages, new browser tabs/windows, etc.). However, PdfKnight does not modify browser settings, and the redirects to portal.pdfknight.com occur only after the shortcut is launched.
PdfKnight could have other capabilities. Most PUAs have data-tracking functionalities, and this might apply to this app. Information of interest may include: visited URLs, viewed webpages, searched queries, Internet cookies, usernames/passwords, personally identifiable details, finance-related data, and so on. The collected information can be shared with and/or sold to third-parties.
To summarize, the presence of software like PdfKnight on devices may result in system infections, serious privacy issues, financial losses, and even identity theft.
| Name | PdfKnight potentially unwanted application |
| Threat Type | PUP (Potentially Unwanted Program), PUA (Potentially Unwanted Application) |
| Supposed Functionality | PDF file format converter |
| Detection Names (installer) | Avast (Win32:Malware-gen), DrWeb (Adware.Linkury.144), ESET-NOD32 (A Variant Of MSIL/MediaArena.C Potentially), Malwarebytes (PUP.Optional.MediaArena), Microsoft (BrowserModifier:MSIL/MediaArena), Full List Of Detections (VirusTotal) |
| Promoted URL | portal.pdfknight.com |
| Detection Names (portal.pdfknight.com) | N/A (VirusTotal) |
| Serving IP Address (portal.pdfknight.com) | 52.165.135.234 |
| Symptoms | A program that you do not recall installing suddenly appeared on your computer. Rogue redirects. Decreased Internet browsing speed. |
| Distribution Methods | Deceptive pop-up ads, free software installers (bundling). |
| Damage | Users are forced to visit the hijacker's website and search the Internet using their search engines. Potential privacy issues and monetary losses. |
| Malware Removal (Windows) | To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
Potentially unwanted application examples
We have investigated countless unwanted apps; PDFtoDocPro, Free PDF Convert, PDFSuperHero, and SumatraPDF are merely some examples of ones that use PDF-centered lures.
PUAs are commonly disguised as legitimate and innocuous software. Users may be enticed into downloading/installing these applications by promises of various "handy" functionalities. However, these functions seldom work as promised, and in most cases – they do not work at all.
It must be stressed that even if a piece of software operates as indicated by its promotional material – that does not prove its legitimacy or safety.
How did potentially unwanted applications install on my computer?
We downloaded PdfKnight from its "official" promotional webpage. Software of this kind is also endorsed on scam sites, which use various lures like scare tactics. Most visitors access these pages via redirects caused by websites using rogue advertising networks, misspelled URLs, intrusive ads, spam browser notifications, and installed adware.
PUAs are distributed using the "bundling" marketing technique as well; in other words – these apps can be packed into installation setups of ordinary programs.
Downloading from freeware and free file-hosting sites, Peer-to-Peer sharing networks, and other dubious channels – poses a threat of bundled content infiltrating the device. The risk is further compounded by rushing through installation processes (e.g., ignoring terms, skipping steps, using "Easy/Quick" settings, etc.).
Additionally, unwanted software is proliferated by intrusive advertisements. When clicked on, some of these adverts can execute scripts to perform stealthy downloads/installations.
How to avoid installation of potentially unwanted applications?
We strongly recommend researching software and downloading only from official/verified sources. Installations must be treated with care, e.g., by reading terms, studying possible options, using the "Custom/Advanced" settings, and opting out of additional apps, extensions, tools, etc.
Another recommendation is to be careful while browsing since fake and malicious online content usually appears legitimate and harmless. For example, while intrusive ads may look innocuous – they redirect to highly questionable sites (e.g., gambling, scam-promoting, adult dating, pornography, etc.).
If you keep encountering such adverts/redirects, inspect the device and immediately remove all suspicious applications and browser extensions/plug-ins. If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate them.
Appearance of portal.pdfknight.com redirecting to the nearbyme.io fake search engine (GIF):
Website promoting PdfKnight application:
Installation setup of PdfKnight application:
PdfKnight's installation folder:
PdfKnight's shortcut details (promoting portal.pdfknight.com):
Instant automatic malware removal:
Manual threat removal might be a lengthy and complicated process that requires advanced IT skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.
Quick menu:
Removal of potentially unwanted applications:
Windows 11 users:
Right-click on the Start icon, select Apps and Features. In the opened window search for the application you want to uninstall, after locating it, click on the three vertical dots and select Uninstall.
Windows 10 users:
Right-click in the lower left corner of the screen, in the Quick Access Menu select Control Panel. In the opened window choose Programs and Features.
Windows 7 users:
Click Start (Windows Logo at the bottom left corner of your desktop), choose Control Panel. Locate Programs and click Uninstall a program.
macOS (OSX) users:
Click Finder, in the opened screen select Applications. Drag the app from the Applications folder to the Trash (located in your Dock), then right click the Trash icon and select Empty Trash.
In the uninstall programs window, look for "PdfKnight" and other suspicious/recently-installed applications, select these entries and click "Uninstall" or "Remove".
After uninstalling the potentially unwanted application, scan your computer for any remaining unwanted components or possible malware infections. To scan your computer, use recommended malware removal software.
Summary:
Commonly, adware or potentially unwanted applications infiltrate Internet browsers through free software downloads. Note that the safest source for downloading free software is via developers' websites only. To avoid installation of adware, be very attentive when downloading and installing free software. When installing previously-downloaded free programs, choose the custom or advanced installation options – this step will reveal any potentially unwanted applications listed for installation together with your chosen free program.
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Frequently Asked Questions (FAQ)
What is the purpose of an unwanted application?
The goal of unwanted software is to generate revenue. Its developers may profit through content promotion (e.g., carried out via redirects, ads, etc.), purchase of fake activation keys, collection/sale of sensitive information, and so on.
Is PdfKnight unwanted application legal?
In most cases, unwanted applications are considered legal because their End User License Agreements (EULA) inform users of their potential behavior.
Is having PdfKnight installed on my computer dangerous?
Unwanted applications typically have undesirable/harmful functionalities, and PdfKnight is no exception. Generally, the presence of PUAs on devices poses the following risks: system infections, severe privacy issues, financial losses, and identity theft.
Will Combo Cleaner help me remove PdfKnight unwanted application?
Yes, Combo Cleaner can detect and remove all types of threats, including unwanted/malicious applications. Note that manual removal (performed without security tools) might not be an ideal solution. In some cases, after a piece of software has been manually removed – file remnants stay hidden within the system. What is more, these components may continue running and causing issues. Therefore, it is paramount to eliminate unwanted software thoroughly.
Outstanding!
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