CVE-2024-57728: SimpleHelp RCE Vulnerability via Zip Slip

CVE-2024-57728 Overview

CVE-2024-57728 is a path traversal vulnerability affecting SimpleHelp remote support software versions 5.5.7 and earlier. The vulnerability allows authenticated admin users to upload arbitrary files anywhere on the file system by exploiting a crafted zip file containing directory traversal sequences—a technique commonly known as "Zip Slip." Successful exploitation can lead to arbitrary code execution on the host system in the context of the SimpleHelp server user.

Critical Impact

Authenticated attackers with admin privileges can achieve arbitrary code execution on SimpleHelp servers by exploiting improper archive extraction handling, potentially compromising entire remote support infrastructure.

Affected Products

• SimpleHelp Remote Support Software v5.5.7 and earlier versions
• All SimpleHelp server deployments running vulnerable versions
• Both Windows and Linux SimpleHelp server installations

Discovery Timeline

• 2025-01-15 - CVE-2024-57728 published to NVD
• 2025-01-31 - Last updated in NVD database

Technical Details for CVE-2024-57728

Vulnerability Analysis

This vulnerability stems from improper validation of file paths during zip archive extraction in the SimpleHelp administrative interface. When an admin user uploads a zip file, the application fails to properly sanitize the file paths contained within the archive entries. An attacker can craft a malicious zip file containing entries with directory traversal sequences (e.g., ../../../) that, when extracted, write files outside the intended upload directory.

The vulnerability is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-59 (Improper Link Resolution Before File Access). The Zip Slip attack vector is particularly dangerous because it allows attackers to overwrite critical system files or place executable payloads in web-accessible directories or startup locations.

Root Cause

The root cause of CVE-2024-57728 is the failure to validate and sanitize file paths within uploaded zip archives before extraction. The SimpleHelp server does not properly check whether extracted file paths remain within the designated target directory. When processing archive entries, the application concatenates the target extraction directory with the file path from the zip entry without validating that the resulting path is still within the intended directory boundary.

Attack Vector

The attack requires network access and authenticated admin-level privileges to the SimpleHelp server. An attacker with valid admin credentials can craft a malicious zip archive containing files with path traversal sequences in their names. When this archive is uploaded through the administrative interface, the extraction process writes files to arbitrary locations on the server's file system.

For example, a zip entry named ../../../etc/cron.d/malicious would write a file to the system's cron directory on Linux systems, enabling scheduled execution of arbitrary commands. On Windows systems, similar techniques can place executables in startup directories or overwrite DLLs for hijacking purposes.

The vulnerability mechanism involves crafting a zip archive where internal file entries contain path traversal characters. When the SimpleHelp server processes the upload, it extracts these entries without validating whether the final destination path escapes the intended directory. For detailed technical analysis, refer to the Horizon3 Attack Research Disclosure.

Detection Methods for CVE-2024-57728

Indicators of Compromise

• Unexpected files appearing in system directories outside SimpleHelp's installation path
• New cron jobs, scheduled tasks, or startup entries not created by administrators
• Modified or newly created files in web server directories or executable paths
• Suspicious zip file uploads in SimpleHelp admin logs containing unusual file paths

Detection Strategies

• Monitor file system activity for writes to sensitive directories (e.g., /etc/cron.d/, Windows startup folders) originating from the SimpleHelp server process
• Analyze SimpleHelp server logs for zip file uploads, particularly those with unusually large numbers of entries or suspicious naming patterns
• Implement file integrity monitoring on critical system directories to detect unauthorized modifications
• Review admin authentication logs for unauthorized or anomalous login activity

Monitoring Recommendations

• Deploy endpoint detection and response (EDR) solutions to monitor process behavior and file system changes on SimpleHelp servers
• Configure SIEM alerts for file creation events in sensitive system directories by the SimpleHelp process
• Enable detailed logging for all administrative actions within SimpleHelp
• Implement network monitoring to detect unusual outbound connections from SimpleHelp servers following potential exploitation

How to Mitigate CVE-2024-57728

Immediate Actions Required

• Upgrade SimpleHelp to a patched version released after January 2025 immediately
• Review admin account credentials and enforce strong authentication policies
• Audit existing admin accounts and remove unnecessary privileged access
• Check file system integrity for signs of previous exploitation

Patch Information

Simple-Help has released security updates addressing this vulnerability. Organizations should upgrade to the latest version of SimpleHelp that includes the fix for this Zip Slip vulnerability. Refer to the Simple Help Security Advisory for specific version information and upgrade instructions.

Workarounds

• Restrict network access to SimpleHelp administrative interfaces using firewall rules or VPN requirements
• Implement additional authentication factors for admin accounts until patching is complete
• Monitor and audit all admin-level actions, particularly file uploads
• Consider temporarily disabling file upload functionality if business operations permit

# Example: Restrict admin interface access via firewall (iptables)
# Allow admin access only from trusted management network
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP