What is BestOffer?
The Malwarebytes research team has determined that BestOffer is adware.
The installer displays advertisements not originating from the sites you are browsing and drops links to advertisements on your desktop.
How do I know if my computer is affected by BestOffer?
You may see these warnings during install:


this entry in your list of installed programs:

and these icons on your desktop and in your taskbar:

How did BestOffer get on my computer?
Adware applications use different methods for distributing themselves. This particular one was bundled with a downloadmanager called Internet Download Manager (IDM).
For clarification, the IDM program discussed was not obtained directly from https://www.internet...oadmanager.com/

How do I remove BestOffer?
Our program Malwarebytes Anti-Malware can detect and remove this potentially unwanted program.
- Please download Malwarebytes Anti-Malware to your desktop.
- Double-click mbam-setup-{version}.exe and follow the prompts to install the program.
- At the end, be sure a check-mark is placed next to:
Launch Malwarebytes Anti-Malware - Then click Finish.
- Once the program has loaded, select Scan Now. Or select the Threat Scan from the Scan menu.
- If an update is available, it will be implemented before the rest of the scanning procedure.
- When the scan is complete, make sure that all Threats are selected, and click Remove Selected.
- Restart your computer when prompted to do so.
- No, Malwarebytes' Anti-Malware removes BestOffer completely.
We hope our application and this guide have helped you eradicate this hijacker.
As you can see below the full version of Malwarebytes Anti-Malware would have protected you against the BestOffer adware. It would have warned you before the adware could install itself, giving you a chance to stop it before it became too late.
The web protection module also blocks some of the connections the installer tries to make:
Technical details for experts
Possible signs in FRST logs:
C:\Users\{username}\Desktop\iStripper.lnk C:\Users\{username}\Desktop\BestOffer EveryDay.lnk Internet Download Manager (HKLM-x32\...\Internet Download Manager) (Version: - Tonec Inc.) Shortcut: C:\Users\{username}\Desktop\BestOffer EveryDay.lnk -> C:\Program Files (x86)\Opera\BestOffer.url () Shortcut: C:\Users\{username}\Desktop\Internet Download Manager.lnk -> C:\Program Files (x86)\Internet Download Manager\IDMan.exe (Tonec Inc.) Shortcut: C:\Users\{username}\Desktop\iStripper.lnk -> C:\Program Files (x86)\Opera\iStripper.url ()Relevant alterations made by the installer:
File system details [View: All details] (Selection) --------------------------------------------------- In the existing folder C:\Program Files (x86)\Opera Adds the file BestOffer.url"="6/29/2016 3:18 PM, 195 bytes, A Adds the file iStripper.url"="6/10/2016 7:46 PM, 193 bytes, A Adds the file Offer.url"="6/25/2016 7:40 AM, 192 bytes, A Adds the file Offer2.url"="6/29/2016 3:17 PM, 195 bytes, A Adds the folder C:\Program Files (x86)\Opera\pic Adds the file idman625build21.exe"="6/13/2016 1:21 PM, 6851184 bytes, A Adds the file istripper.ico"="6/10/2016 7:20 PM, 122192 bytes, A Adds the file offer.ico"="2/16/2016 4:52 AM, 353118 bytes, A In the existing folder C:\Users\{username}\Desktop Adds the file BestOffer EveryDay.lnk"="8/18/2016 3:08 PM, 1067 bytes, A Adds the file Internet Download Manager.lnk"="8/18/2016 3:09 PM, 1009 bytes, A Adds the file iStripper.lnk"="8/18/2016 3:08 PM, 1075 bytes, A In the existing folder C:\Users\{username}\Downloads Adds the file idman625build21.exe"="8/18/2016 1:54 PM, 7586688 bytes, AMalwarebytes Anti-Malware log:
Malwarebytes Anti-Malware www.malwarebytes.org Scan Date: 8/18/2016 Scan Time: 3:50 PM Logfile: mbamIDM.txt Administrator: Yes Version: 2.2.1.1043 Malware Database: v2016.08.18.04 Rootkit Database: v2016.08.15.01 License: Premium Malware Protection: Disabled Malicious Website Protection: Disabled Self-protection: Enabled OS: Windows 7 Service Pack 1 CPU: x64 File System: NTFS User: {username} Scan Type: Threat Scan Result: Completed Objects Scanned: 318481 Time Elapsed: 7 min, 33 sec Memory: Enabled Startup: Enabled Filesystem: Enabled Archives: Enabled Rootkits: Enabled Heuristics: Enabled PUP: Enabled PUM: Enabled Processes: 0 (No malicious items detected) Modules: 0 (No malicious items detected) Registry Keys: 0 (No malicious items detected) Registry Values: 0 (No malicious items detected) Registry Data: 0 (No malicious items detected) Folders: 0 (No malicious items detected) Files: 5 PUP.Optional.Downloader, C:\Users\{username}\Downloads\idman625build21.exe, Quarantined, [0488cc80f5a50d295910973c07fdad53], PUP.Optional.BestOffer, C:\Users\{username}\Desktop\BestOffer EveryDay.lnk, Quarantined, [216b5bf14654c67017fbe5cbe61e4bb5], PUP.Optional.BestOffer, C:\Program Files (x86)\Opera\BestOffer.url, Quarantined, [4a42420ab1e988ae56a2941dcf350ef2], PUP.Optional.BestOffer, C:\Program Files (x86)\Opera\Offer.url, Quarantined, [98f4cd7fdebc47ef47b32e83679df50b], PUP.Optional.BestOffer, C:\Program Files (x86)\Opera\Offer2.url, Quarantined, [721aa3a9e2b8ad89c5393b76877d01ff], Physical Sectors: 0 (No malicious items detected) (end)As mentioned before the full version of Malwarebytes Anti-Malware could have protected your computer against this threat.
We use different ways of protecting your computer(s):
- Dynamically Blocks Malware Sites & Servers
- Malware Execution Prevention