Incredimail

Overview

Adware:Win32/Incredimail is a detection for the legacy, highly controversial email client 'IncrediMail'. While technically a functional email application, its extremely aggressive monetization tactics, bundled toolbars, and heavy tracking led most major antivirus vendors to classify it as a Potentially Unwanted Program (PUP) or Adware. The company officially shut down in 2020, but legacy installers continue to circulate, presenting security risks.

Understanding Incredimail (Legacy Adware)
To an end-user, Incredimail offered a flashy interface with animated emoticons and custom backgrounds. However, the 'free' version came at a steep cost: the software forcibly changed browser homepages, appended advertising signatures to every outgoing email, and installed aggressive tracking toolbars. For a security team, legacy software like this represents an unpatched attack surface (`T1190`) and a vector for data leakage.

Execution and Intrusive Mechanics
When installed (`T1204.002`), Incredimail often bundled third-party 'search protectors' (like the MyStart or Perion search hijackers) (`T1189`). It established deep persistence (`T1547.001`) and aggressively hooked into browser settings (`T1112`) to redirect search traffic to affiliate networks, generating ad revenue. Furthermore, because the software is now entirely defunct and unsupported, any existing installations contain unpatched vulnerabilities that can be exploited by remote attackers or local privilege escalation exploits.

Indicators of Compromise & Impact
The primary impact is a severe degradation of the browsing experience, privacy violations via data collection, and the presence of end-of-life (EOL) vulnerable software on the endpoint. Host-based IoCs include the presence of `IncrediMail.exe`, the 'MyStart by IncrediMail' browser extensions, and registry modifications forcing browser homepages to Incredimail's legacy portals.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_INCREDIMAIL {
    meta:
        description = "Detects Incredimail (advanced_threat)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "incredimail" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Incredimail Activity
id: 41d0956d87dd96ff15343f48663ff8de
status: experimental
description: Detects generic indicators of the incredimail malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*incredimail*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Use the Windows Control Panel to thoroughly uninstall the 'IncrediMail' application and any associated toolbars (e.g., MyStart, Perion).
2. Migrate the user's email accounts to a secure, enterprise-supported email client (like Outlook or Thunderbird).
3. Reset all installed web browsers to their default settings to clear out hijacked homepages and search engines.
4. Run a thorough scan with an Adware removal tool to clean up deep registry persistence mechanisms left behind by the installer.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not allow users to continue using Incredimail; the software is defunct, unsupported, and represents a significant security vulnerability.
2. Avoid simply changing the browser homepage manually; the bundled adware services will likely revert the changes upon the next reboot.

References & External Analysis

• Search "incredimail" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: advanced_threat)

Explore other malware families in the same category:

• Mapsgory
• Installmonetizer
• Linkular
• Daum
• Tsingsoft

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/incredimail.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.