CVE-2025-33136 Overview
CVE-2025-33136 affects IBM Aspera Faspex versions 5.0.0 through 5.0.12. The vulnerability stems from improper protection of assumed immutable data [CWE-471]. An authenticated user can obtain sensitive information or perform unauthorized actions on behalf of another user. IBM Aspera Faspex is a managed file transfer solution used by enterprises to exchange large files and datasets across organizations.
The flaw allows attackers with valid low-privilege credentials to compromise confidentiality, integrity, and availability of the application. Successful exploitation requires no user interaction and can be performed over the network.
Critical Impact
An authenticated attacker can act on behalf of other Faspex users, accessing sensitive transfers and triggering unauthorized actions across the file transfer workflow.
Affected Products
- IBM Aspera Faspex 5.0.0 through 5.0.12
- Deployments running on Linux kernel platforms
- Enterprise file transfer environments using affected Faspex releases
Discovery Timeline
- 2025-05-22 - CVE-2025-33136 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-33136
Vulnerability Analysis
The vulnerability is classified under [CWE-471] Modification of Assumed-Immutable Data (MAID). Faspex treats certain data fields as immutable after creation, but fails to enforce that assumption at the server side. An authenticated user can modify these fields and cause the application to act on the manipulated values.
Because the application trusts the assumed-immutable values for authorization or identity decisions, tampering enables impersonation and unauthorized operations. The attack requires only low privileges, which any provisioned Faspex user holds. No user interaction is needed to complete exploitation.
Root Cause
The root cause is missing server-side validation of data elements the application treats as immutable. Client-supplied identifiers, references, or state values are accepted without verifying that the requesting user owns or is authorized for the referenced object. This pattern enables horizontal privilege escalation across Faspex user accounts.
Attack Vector
The attack is network-based and authenticated. An attacker with a valid Faspex account submits crafted requests to the Faspex API or web interface with modified identifiers. The server processes the request in the context of another user, returning sensitive transfer data or executing privileged operations. Refer to the IBM Support Page for vendor technical details.
Detection Methods for CVE-2025-33136
Indicators of Compromise
- Faspex audit log entries showing one authenticated user accessing transfers or metadata belonging to another user account
- Unexpected API calls referencing object identifiers that do not belong to the authenticated session
- Requests with manipulated user, package, or workgroup identifiers from low-privilege accounts
Detection Strategies
- Compare the authenticated session user against the owner of each accessed resource in Faspex application logs
- Alert on anomalous access patterns where a single account interacts with resources across many other users in a short window
- Inspect web server and reverse proxy logs for tampered request parameters targeting Faspex endpoints
Monitoring Recommendations
- Forward Faspex application, web server, and authentication logs to a centralized SIEM for correlation
- Baseline normal per-user transfer activity and alert on deviations such as bulk cross-user access
- Monitor Linux host telemetry on Faspex servers for unusual outbound data flows following authenticated sessions
How to Mitigate CVE-2025-33136
Immediate Actions Required
- Upgrade IBM Aspera Faspex to a fixed release per the IBM Support Page
- Audit existing Faspex user accounts and disable inactive or unnecessary credentials to reduce the authenticated attack surface
- Review recent Faspex audit logs for cross-user access that predates the patch
Patch Information
IBM has published a security bulletin and updated Faspex packages addressing CVE-2025-33136. Administrators should consult the IBM Support Page for the specific fixed version and upgrade procedure for Faspex 5.0.x deployments.
Workarounds
- Restrict network access to the Faspex web interface and API to trusted networks and VPN segments
- Enforce strong authentication and short session lifetimes to limit abuse of compromised low-privilege accounts
- Apply least-privilege role assignments so users hold only the minimum Faspex permissions required
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
