CVE-2018-25366 Overview
CVE-2018-25366 is a stack-based buffer overflow [CWE-120] in Globalscape CuteFTP 5.0 XP. The flaw resides in the Site Manager label field, which fails to validate input length before copying data into a fixed-size stack buffer. A local attacker who supplies a label string longer than 520 bytes can overwrite the saved return address and redirect execution to attacker-controlled shellcode. Exploitation triggers when a desktop shortcut created from the malicious site entry is launched. The condition was published to the Exploit-DB #45259 database and detailed in the VulnCheck CuteFTP Advisory.
Critical Impact
A local attacker can achieve arbitrary code execution in the context of the user running CuteFTP 5.0 XP by abusing the Site Manager label field.
Affected Products
- Globalscape CuteFTP 5.0 XP
- Installer distributed at cuteftp50.exe from the Globalscape archive
- Windows hosts running the affected client build
Discovery Timeline
- 2026-05-25 - CVE-2018-25366 published to NVD
- 2026-05-26 - Last updated in NVD database
Technical Details for CVE-2018-25366
Vulnerability Analysis
The vulnerability is a classic stack-based buffer overflow in the Site Manager component of CuteFTP 5.0 XP. The application stores user-supplied site labels in a fixed-size stack buffer without enforcing length checks. Supplying a label greater than 520 bytes corrupts adjacent stack frames, including the saved return address. When the user creates a desktop shortcut from the affected site entry and launches it, the corrupted return address is dereferenced and control flow transfers to attacker-supplied bytes. The attack vector is local because the malicious data must be entered into the Site Manager dialog of the installed client.
Root Cause
The root cause is missing bounds validation on the Site Manager label field. CuteFTP 5.0 XP performs an unchecked copy of the label string into a stack buffer, matching the [CWE-120] classic buffer copy without size checking pattern. The product predates modern compiler mitigations such as stack canaries, SafeSEH, and ASLR, leaving the saved return address trivially reachable.
Attack Vector
An attacker with local access opens the CuteFTP Site Manager and creates or edits a site whose label contains a crafted payload exceeding 520 bytes. The payload contains a NOP sled, shellcode, and a return address that pivots execution into the shellcode. When a shortcut is created from the malicious site entry and subsequently launched, the overflow triggers and the shellcode executes in the context of the current user. Refer to the Exploit-DB #45259 entry and the VulnCheck CuteFTP Advisory for the structured payload layout and exploitation steps.
Detection Methods for CVE-2018-25366
Indicators of Compromise
- Presence of cuteftp.exe or cuteftp50.exe from the Globalscape archive on Windows endpoints.
- CuteFTP Site Manager configuration files containing label strings longer than 520 bytes or containing non-printable byte sequences consistent with shellcode.
- Newly created desktop shortcuts (.lnk) pointing to CuteFTP site entries with anomalously long target names.
- CuteFTP process spawning unexpected child processes such as cmd.exe, powershell.exe, or rundll32.exe.
Detection Strategies
- Inventory endpoints for installed CuteFTP 5.0 XP and flag any instance for review or removal.
- Monitor process creation events where cuteftp.exe is the parent of a shell or scripting interpreter.
- Inspect CuteFTP configuration storage and .lnk files for label fields exceeding the 520-byte threshold.
Monitoring Recommendations
- Enable command-line and process lineage logging on Windows endpoints to capture CuteFTP child process activity.
- Alert on shortcut creation events targeting legacy FTP clients in user profile directories.
- Forward endpoint telemetry to a centralized analytics platform for behavioral correlation across hosts.
How to Mitigate CVE-2018-25366
Immediate Actions Required
- Uninstall CuteFTP 5.0 XP from all managed endpoints. The product is end-of-life and no vendor patch is available.
- Replace the client with a maintained, supported FTP/SFTP client that receives security updates.
- Restrict execution of legacy CuteFTP binaries using application control or AppLocker policies.
- Audit endpoints for existing CuteFTP Site Manager configurations and remove any unexpected entries.
Patch Information
No vendor patch is available for CuteFTP 5.0 XP. The installer remains accessible via the Globalscape CuteFTP Installer archive for reference but should not be deployed. Organizations must migrate to a supported file transfer client.
Workarounds
- Remove the CuteFTP 5.0 XP installation directory and associated registry keys.
- Block execution of cuteftp.exe through application allow-listing where uninstallation is not immediately feasible.
- Restrict local user privileges to limit the impact of arbitrary code execution under the user context.
# Configuration example: block legacy CuteFTP execution via PowerShell AppLocker rule
New-AppLockerPolicy -RuleType Path -User Everyone `
-RuleNamePrefix "Block-CuteFTP-CVE-2018-25366" `
-Action Deny `
-Path "%PROGRAMFILES%\GlobalSCAPE\CuteFTP\cuteftp.exe"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
