Threat Descriptions

Adware:W32/Apropos

Classification

Category :

Spyware

Type :

AdwareSpyware

Platform :

W32

Aliases :

ContextPlus, Adintelligence.AproposToolbar, PeopleOnPage

Summary

This program delivers advertising content to the user. It is usually annoying but harmless, unless it is combined with spyware or trackware.

Removal

Based on the settings of your F-Secure security product, it may block the file from running, move it to the quarantine where it cannot spread or cause harm, or ask you to select an action.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Adware:W32/Apropos is a program that collects data on the user's browsing behavior in order to display targeted advertising content during each Web browsing session.

The program also uses a rootkit and highly sophisticated stealth techniques to avoid detection.

Please note that Apropos is not associated with Apropos Technologies, Inc (NASDAQ: APRS). The Apropas spyware family is produced by PeopleOnPage.

Installation

Apropos silently itself into a randomly named directory under the Program Files folder. Each installation is assigned a unique ID.

It also installs:

  • One randomly named EXE file to the System32 folder
  • One randomly named SYS file to the \System32\Drivers folder

In addition to the randomly named files, Apropos uses several statically named files that reside in the installation directory, such as ace.dll, data.bin and WinGenerics.dll. These files can be seen below (images from a log file):

Rootkit

Once installed, Apropos's rootkit implements a kernel-mode driver. The rootkit starts automatically early in the boot process and modifies important data structures and several native API functions in order to hide files, directories, registry keys and processes related to the adware.

Specifically, the following functions are patched:

  • NtCreateKey
  • NtOpenKey
  • NtEnumerateKey
  • IoCreateFile
  • NtQueryDirectoryFile
  • NtQuerySystemInformation

Once the files and registry keys have been hidden, no user-mode process is allowed to access them.

Remote Connection

Apropos collects information about the computer system and tracks the user's browsing habits. The collected information is forwarded to remote servers, together with the unique ID.

These servers run the ContextPlus engine, which is used by the public software POP! (also made by PeopleOnPage). When the client connects to the server, the name Apropos is used as the client name.

The ContextPlus engine tracks the following information related to the unique ID:

  • Softwares installed on the machine
  • User's browsing behavior
  • Web sites visited

The information is used to return targeted advertising content whenever the application contacts the remote server.