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The vulnerability stems from improper path sanitization during ZIP archive extraction. An authenticated admin user can upload a malicious ZIP file containing directory traversal sequences (e.g., ../../) in filenames.
During extraction, the application fails to validate or neutralize these sequences, allowing the file to be written outside the intended upload directory.
By crafting a ZIP file with relative path elements, an attacker can target the underlying operating system’s file structure, writing arbitrary files anywhere the SimpleHelp server process has write permissions.
A common technique is to overwrite executable scripts, configuration files, or libraries that get loaded by the server or other scheduled processes.
Because the attack chains directory traversal (CWE-22) with improper link resolution (CWE-59), it can bypass directory restrictions and create or replace sensitive system files.
Once the arbitrary file is placed, the attacker can trigger execution—either immediately through a separate entry point or by waiting for the system to load the compromised file naturally.
The attack is particularly potent because the malicious ZIP upload is part of a legitimate administrative feature, making it easier to blend into normal activity.
Successful exploitation leads to remote code execution with the privileges of the SimpleHelp server user, which often includes high‑level system access on the host.
dailycve form:
Platform: SimpleHelp
Version: ≤5.5.7
Vulnerability : Zip Slip
Severity: High
date: 2025‑01‑15
Prediction: 2025‑01‑31
What Undercode Say:
Simulate a malicious ZIP payload (conceptual)
zip -r evil.zip ../../../../etc/cron.d/root_script --symlinks
Extract traversal patterns
unzip -l evil.zip | grep '../'
Check for unpacking without sanitization
python3 -c "import zipfile; z=zipfile.ZipFile('evil.zip'); z.extractall('/target/', pwd=None)"
Exploit:
An attacker obtains admin credentials and uses the file upload feature to submit a ZIP file with path traversal entries (like ../../../bin/webshell). The server writes the file to an arbitrary location, then the attacker invokes that file via a separate HTTP request to gain a reverse shell.
Protection from this CVE
Upgrade to SimpleHelp version 5.5.8 or later. If upgrade is not immediate, restrict admin access to only absolutely trusted users. Use file integrity monitoring to detect unauthorised file writes outside expected directories, and consider application‑level ZIP sanitisation or proxy content filtering.
Impact
Complete host compromise. An attacker with admin privileges can achieve remote code execution, steal sensitive data, backdoor system binaries, and pivot to other internal hosts. The impact is magnified because the flaw allows file placement anywhere on the filesystem, not just within the application’s own directory.
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Sources:
Reported By: www.cve.org
Extra Source Hub:
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