Papras

Overview

Papras (classified across cybersecurity vendors as Trojan:Win32/Papras, PWS:Win32/Papras, and Trojan-PSW.Win32.Papras) is a modular password stealer and banking trojan family targeting Windows environments. Disseminated primarily via malicious spam attachments and exploit kits, Papras executes memory-resident credential scraping routines. It extracts stored user account credentials, autofill data, session cookies, and digital certificates from popular web browsers (Chrome, Firefox, Internet Explorer/Edge) and email clients (Outlook, Thunderbird), as well as FTP clients (FileZilla, Total Commander). Papras injects its payload into legitimate processes (such as svchost.exe or explorer.exe) to evade security hooks, encrypting exfiltrated logs via RC4 or AES before transmitting them over HTTP/HTTPS to remote command-and-control servers.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Papras
• PWS:Win32/Papras
• Trojan-PSW.Win32.Papras
• Win32/Papras
• Papras Stealer

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.
• T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_PAPRAS_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Papras"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "papras" ascii wide nocase
        $s2 = "trojan:win32/papras" ascii wide nocase
        $s3 = "pws:win32/papras" ascii wide nocase
        $s4 = "trojan-psw.win32.papras" ascii wide nocase
        $s5 = "win32/papras" ascii wide nocase
        $s6 = "papras stealer" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Papras (Infostealer) Execution & Triage
id: ce2c186b-c214-5154-854f-c8693377202c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Papras malware family. Detects browser credential database harvesting,
  master key queries, and DPAPI extraction routines typical of modern infostealers.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/papras
- https://malware-families-catalog.systemhelpdesk.com/defensive/infostealer-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.infostealer
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1555_003
- attack.t1555_004
- attack.t1055
- attack.t1547_001
- attack.t1041
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \rundll32.exe
    CommandLine|contains:
    - \Google\Chrome\User Data\Default\Login Data
    - \AppData\Roaming\Mozilla\Firefox\Profiles
    - \AppData\Local\Microsoft\Edge\User Data
    - vaultcmd.exe /list
    - dpapi
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_PAPRAS_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Papras tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "papras" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

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

1. Instantly isolate the endpoint; the attacker possesses real-time capability to intercept web traffic and manipulate banking sessions.
2. Initiate an immediate password reset for all financial, corporate, and personal accounts accessed from the infected machine, utilizing a clean device.
3. Capture a forensic memory image (RAM dump) to extract the decrypted C2 addresses and the specific web inject configuration files (target lists).
4. Perform a clean OS rebuild, as banking trojans often establish deep, redundant persistence mechanisms that are difficult to fully eradicate.

What to Avoid

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

1. Do not allow the user to continue accessing financial portals while 'monitoring' the threat; the MitB capability intercepts traffic before encryption.
2. Avoid ignoring sudden spikes in outbound network traffic, as the infected machine may be actively participating in a DDoS extortion campaign.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Trojan:Win32/Papras
• Trend Micro Security Research - PWS.Win32.Papras Overview
• MITRE ATT&CK - Credentials from Password Stores: Web Browsers (T1555.003)
• Search "papras" on VirusTotal (External Analysis)
• Search "papras" on Any.Run (Sandbox Sandbox)
• Search "papras" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Infostealer)

Explore other documented threats in the same operational category:

• Ldpinch
• Advpassman
• Bypass
• Lynx
• Spytector
• Adspy
• Lumma
• Chisburg

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/papras.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.