Expiro

Category: file_infector · Aliases: xpiro · Sample count (EMBER 2018): 305 · Enrichment: curated_sourced · Updated: 2026-06-11
Category: File_InfectorActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Expiro (also known as Xpiro) is a file infector that has been active for over a decade and continues to be updated by its authors. It infects executable files on both 32-bit and 64-bit Windows systems by inserting its own code into them. Beyond classic file infection, Expiro has information-stealing capabilities: it can install browser extensions, alter the security settings and behaviour of an infected system, and steal data such as account credentials. Its infection routine was notably revised in samples observed around 2017. Expiro is documented by Fraunhofer FKIE's Malpedia and has been analysed by vendors including McAfee.

Known aliases

Threat reports may refer to this family under multiple names:

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_EXPIRO {
    meta:
        description = "Detects Expiro (file_infector)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "expiro" ascii wide nocase
        $s2 = "xpiro" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Expiro Activity
id: 1ffe01c89da9e1b722222b1e92936db4
status: experimental
description: Detects generic indicators of the expiro malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*expiro*"
            - "*xpiro*"
    condition: selection
level: medium

References & External Analysis

Frequently Asked Questions

What is Expiro?

Expiro, also known as Xpiro, is a file infector virus that has been active for more than a decade. It infects executable files on 32-bit and 64-bit Windows systems and also includes information-stealing functionality.

How does Expiro infect a system?

As a file infector, Expiro inserts its code into legitimate Windows executable files so that the malicious code runs when an infected program is launched. It is capable of infecting both 32-bit and 64-bit executables, and its infection routine was revised in samples seen around 2017.

What can Expiro do besides infecting files?

Beyond spreading through executables, Expiro can install browser extensions, change the security settings and behaviour of an infected system, and steal information such as account credentials.

What sources document Expiro?

Expiro is profiled in Fraunhofer FKIE's Malpedia and has been analysed in named-vendor research, including work by McAfee. These sources describe it as a long-running, frequently updated file infector with credential-theft capabilities.

How do I remove the Expiro File_Infector from Windows?

Manual removal of Expiro is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.

Is Expiro a virus or a File_Infector?

Expiro is classified as a File_Infector. Unlike traditional viruses that infect files, modern malware like Expiro typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a Expiro infection?

Symptoms of Expiro can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.

Related Families (Category: file_infector)

Explore other malware families in the same category:

Protect Your Network Against File_Infectors

Want to prevent Expiro and similar threats from compromising your organization? Read our comprehensive defensive guide: Suspect an Infection? What to do.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

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