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Introduction
A sophisticated phishing campaign is actively leveraging fake Adobe Document Cloud pages to deploy ScreenConnect, a legitimate remote monitoring and management (RMM) tool, as an initial access vector against financial organizations. The attack chain exploits user trust in the Adobe brand, using compromised WordPress sites and advanced evasion techniques to silently install remote access software that enables full system takeover, data exfiltration, and lateral movement. Understanding this RMM abuse technique is critical for defenders, as traditional signature-based antivirus solutions often fail to detect the installation of legitimate software repurposed for malicious ends.
Learning Objectives
- Understand the complete attack chain of Adobe-themed phishing campaigns delivering ScreenConnect, from initial lure to post-exploitation activities
- Identify key detection techniques including network IOCs, Windows event log monitoring, and behavioral indicators for unauthorized RMM installation
- Implement practical mitigation strategies, including email filtering, endpoint isolation procedures, and preventative hardening against legitimate tool abuse
You Should Know
- Anatomy of the Attack Chain – From Phishing Lure to Remote Access
The campaign begins with phishing emails that mimic legitimate Adobe Document Cloud file-sharing notifications, informing recipients that a confidential project document has been uploaded due to size or confidentiality constraints. These emails direct victims to compromised WordPress websites hosting a sophisticated phishing kit named RatPressto, which is specifically designed to deliver ScreenConnect-based remote access malware.
Upon visiting the fake Adobe page, victims are presented with a counterfeit document delivery confirmation interface, often accompanied by CAPTCHA challenges such as Cloudflare Turnstile. These CAPTCHA mechanisms serve dual malicious purposes: they bypass automated security scanners that cannot solve CAPTCHAs, and they create a false sense of legitimacy for the victim. The multi-stage evasion is further enhanced by routing traffic through legitimate Adobe infrastructure—specifically, the Adobe Target A/B testing platform hosted on omtrdc.net domains—before redirecting to attacker-controlled servers.
The payload delivery employs in-memory execution techniques to evade signature-based defenses. Researchers from Zscaler ThreatLabz identified this attack chain as early as February 2026, noting that the adversary uses .NET reflection to keep payloads in memory only, bypassing traditional antivirus detection and hindering forensic examination. The ScreenConnect MSI is often delivered via phishing attachments or downloaded directly from malicious domains, then installed silently using `msiexec.exe` with command-line parameters that suppress user interface elements and user interaction.
Step-by-step guide – Hunting for unauthorized ScreenConnect installations:
On Windows (EDR/Endpoint Investigation):
Step 1: Check for ScreenConnect service installation (look for unauthorized instances)
Get-Service | Where-Object {$_.DisplayName -like "ScreenConnect"}
Step 2: Search for ScreenConnect MSI execution events in Event Logs
Get-WinEvent -FilterHashtable @{LogName='Application'; ProviderName='MsiInstaller'} |
Where-Object {$_.Message -like "ScreenConnect"} | Format-List
Step 3: Examine Task Scheduler for persistence mechanisms
schtasks /query /fo LIST /v | findstr /i "screenconnect"
Step 4: Locate ScreenConnect client installation directories
Get-ChildItem -Path "C:\Program Files\ScreenConnect", "C:\Program Files (x86)\ScreenConnect" -ErrorAction SilentlyContinue
Step 5: Identify suspicious msiexec executions with silent installation flags
Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4688} |
Where-Object {$_.Message -match "msiexec./quiet"} | Format-List
On Linux (if RMM tools are deployed in cross-platform environments):
Step 1: Check running processes for ScreenConnect components ps aux | grep -i screenconnect Step 2: Search for ScreenConnect installation artifacts find /opt /usr/local -name "screenconnect" -type f 2>/dev/null Step 3: Check systemd services systemctl list-units | grep -i screenconnect Step 4: Review recent package installations grep -i "screenconnect" /var/log/dpkg.log /var/log/yum.log 2>/dev/null
- Vulnerability Exploitation – CVE-2026-3564 and Authentication Bypass Risks
Compounding the phishing threat is a recently patched critical vulnerability in ScreenConnect itself. Tracked as CVE-2026-3564, this flaw carries a CVSS score of 9.0 (Critical) and allows attackers to extract unique machine keys and hijack active ScreenConnect sessions by abusing ASP.NET machine keys to forge trusted authentication. The vulnerability affects all ScreenConnect versions prior to 26.1, exposing unpatched servers to session hijacking, privilege escalation, and unauthorized remote access.
If attackers successfully install an outdated or vulnerable version of ScreenConnect through the initial phishing vector, they can leverage CVE-2026-3564 to escalate their access, extract sensitive configuration data, and move laterally across the network. ConnectWise has released patches, but many organizations may unknowingly run vulnerable versions installed via malicious campaigns, creating a persistent backdoor.
Step-by-step guide – Patching and vulnerability assessment:
On Windows – Check installed ScreenConnect version
Get-ItemProperty "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\" |
Where-Object {$_.DisplayName -like "ScreenConnect"} |
Select-Object DisplayName, DisplayVersion
Alternative: Check via registry for ScreenConnect server installations
Get-ItemProperty "HKLM:\SOFTWARE\WOW6432Node\ScreenConnect" -ErrorAction SilentlyContinue
On Linux – Check version (if ScreenConnect server is deployed)
screenconnect --version
OR
cat /opt/screenconnect/version.txt 2>/dev/null
Block known malicious ScreenConnect relay domains via Windows Firewall
New-NetFirewallRule -DisplayName "Block Malicious SC Domains" -Direction Outbound -Action Block -RemoteAddress "193.42.11.108" Example C2 IP from campaign
For enterprise environments – Use PowerShell to uninstall unauthorized ScreenConnect instances
$sc = Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "ScreenConnect"}
if ($sc) { $sc.Uninstall() }
- Detection Strategies – IOCs, Network Monitoring, and Behavioral Analytics
Security teams must adopt a multi-layered detection approach that goes beyond traditional signature matching. The legitimate nature of ScreenConnect means that its presence on an endpoint is not inherently malicious—context and behavioral analysis are essential.
Key Indicators of Compromise (IOCs) identified from the campaign include:
Network IOCs:
- C2 IPs:
188.214.34.20:34123, `169.40.2.68:45191`
– Malicious domains:ado-read-parser.com, `zx.ado-read-parser.com` (resolves to188.214.34.20)
Behavioral Indicators to Monitor:
- msiexec.exe executed with `/quiet` or `/passive` flags followed by ScreenConnect binary execution
- ScreenConnect service installation with non-standard naming or unusual installation paths
- Outbound connections on port 8041 (default ScreenConnect relay port)
- Presence of “Adobe Synchronizer” string within the HTTP User-Agent field in outbound traffic
Step-by-step guide – Deploy detection rules and network monitoring:
Linux – Monitor for suspicious outbound connections using netstat watch -n 2 'netstat -tunap | grep -E "8041|443|45191" | grep -i screenconnect' Extract and monitor User-Agent strings from proxy logs grep -E "Adobe Synchronizer" /var/log/nginx/access.log Windows – Enable advanced audit logging for process creation auditpol /set /subcategory:"Process Creation" /success:enable /failure:enable Sigma rule example – Detect ScreenConnect MSI followed by guest session (implement in SIEM) Detection: ProcessCreation with Image contains "msiexec.exe" AND CommandLine contains "ScreenConnect" AND CommandLine contains "/quiet" Followed by NetworkConnection to port 8041 within 60 seconds Block malicious IPs at the firewall level (Linux iptables example) iptables -A OUTPUT -d 188.214.34.20 -j DROP iptables -A OUTPUT -d 169.40.2.68 -j DROP Windows Firewall block via netsh netsh advfirewall firewall add rule name="Block SC C2" dir=out remoteip=188.214.34.20,169.40.2.68 action=block
- Mitigation and Hardening – Preventing RMM Tool Abuse
The most effective defense against ScreenConnect abuse is to prevent unauthorized installation in the first place. Organizations should implement application allowlisting to restrict which executables can run, and use Windows Defender Application Control (WDAC) or AppLocker to block unsigned or untrusted MSI installers. Since ScreenConnect is a legitimate tool, many IT environments allow it—attackers exploit this trust by installing it under the radar. A Zero Trust approach that requires explicit approval for any RMM tool installation is essential.
Additional preventative measures include disabling JavaScript in Adobe Reader where business requirements permit, as this kills many PDF-based exploit chains at the source. Individual users can disable JavaScript via Edit > Preferences > JavaScript in Adobe Reader, while enterprise environments should deploy the registry-based configuration as documented by Adobe. Network-level filtering of CAPTCHA bypass mechanisms and monitoring for `omtrdc.net` redirect chains can also help detect phishing attempts before payload delivery.
Step-by-step guide – Hardening endpoints and email gateways:
Windows – Disable msiexec silent installation for non-admin users via Software Restriction Policies New-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\Installer" -Name "DisableMSI" -Value 2 -PropertyType DWORD -Force Windows – Block ScreenConnect from loading via WDAC (requires audit mode first) Generate WDAC policy scanning for ScreenConnect binaries New-CIPolicy -FilePath "C:\WDAC\SCPolicy.xml" -Level Publisher -Fallback Hash, FilePath -UserPEs Deploy email filtering rules for CAPTCHA-based phishing (Exchange Online example) New-TransportRule -Name "Block CAPTCHA URL Patterns" -SubjectContainsWords "Adobe Document Cloud","secure file" -AttachmentContainsWords "turnstile","captcha" -SetAuditSeverity High Registry-based disable of JavaScript in Adobe Reader (enterprise deployment) reg add "HKEY_CURRENT_USER\Software\Adobe\Adobe Acrobat\DC\JSPrefs" /v "bEnableJS" /t REG_DWORD /d 0 /f Linux – Restrict execution of RMM tools using AppArmor sudo aa-genprof /opt/screenconnect/screenconnect-service
5. Incident Response – Containment and Eradication Procedures
When an unauthorized ScreenConnect installation is detected, immediate containment is critical. Attackers often use the RMM connection to deploy additional malware, harvest credentials, establish persistence, and move laterally across the network.
Step-by-step guide – Incident response workflow:
- Immediate Isolation: Disconnect the affected endpoint from the network to prevent ongoing C2 communication and lateral movement
-
Service Termination: Stop and disable the ScreenConnect service:
Windows Stop-Service -Name "ScreenConnect" -Force Set-Service -Name "ScreenConnect" -StartupType Disabled Linux sudo systemctl stop screenconnect sudo systemctl disable screenconnect
- Malware Removal: Uninstall ScreenConnect and delete residual files:
Windows – Silent uninstall using product GUID (retrieve GUID from registry)
$sc = Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "ScreenConnect"}
$sc.Uninstall()
Clean up installation directories and temporary files
Remove-Item "C:\Program Files\ScreenConnect" -Recurse -Force -ErrorAction SilentlyContinue
Remove-Item "$env:TEMP.msi" -Filter "ScreenConnect" -Force
- Credential Reset: Force password resets for the compromised user and any accounts accessed during the incident. Revoke all active session tokens and API keys.
-
Forensic Analysis: Collect ScreenConnect logs (located at `%ProgramData%\ScreenConnect\` on Windows) and correlate with EDR telemetry to identify attacker actions, data exfiltration, and lateral movement indicators.
-
Block IOCs: Block identified malicious IPs, domains, and URLs at the perimeter firewall and web proxy.
What Undercode Say
-
Trusted tools are the new malware delivery vector. Attackers are increasingly bypassing security controls by leveraging legitimate remote access tools. This “Living Off the Land” approach requires defenders to shift from reputation-based blocking to behavioral detection and Zero Trust access controls.
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Defense must be layered and adaptive. No single control can stop these multi-stage attacks. Effective protection requires email security, user awareness training, endpoint detection and response, network monitoring, and rapid incident response working in concert.
The financial sector has become the primary target of this campaign, with attackers leveraging the RatPressto phishing kit to deliver ScreenConnect as a persistent remote access backdoor. What makes this technique particularly insidious is that traditional antivirus solutions, focused on detecting custom malware, will not flag the installation of a legitimate RMM tool. Defenders must therefore implement application allowlisting, monitor for unauthorized RMM installations via EDR behavioral rules, and establish strict change management processes requiring explicit approval for any remote access software deployment. User training remains equally critical—employees must be taught to verify “Adobe Document Cloud” notifications, hover over links before clicking, and report suspicious emails rather than interact with them.
Prediction
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- Increased adoption of RMM-specific detection rules in SIEMs and EDR platforms – Security vendors will accelerate development of behavioral analytics that flag unauthorized RMM installations, silent MSI executions, and anomalous remote session patterns.
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- Escalation of social engineering sophistication – Attackers will invest heavily in AI-generated phishing lures that perfectly replicate brand communications, including dynamic personalization, voice phishing (vishing) callbacks, and deepfake video messages that bypass existing awareness training.
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- Regulatory pressure on software vendors – Governments and industry regulators will introduce stricter requirements for RMM tools, including mandatory multi-factor authentication, installation logging, and default configurations that prevent silent or unattended installations without explicit user consent.
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