Introduction
In a recent security disclosure, Amazon Web Services (AWS) has revealed a critical vulnerability in its WorkSpaces client for Linux, identified as CVE-2025-12779.
This flaw, stemming from improper handling of authentication tokens, could enable unauthorized local users to extract valid tokens and gain access to other users' virtual desktops.
The issue was publicly announced on November 5, 2025, through AWS's security bulletin AWS-2025-025, highlighting the potential risks for organizations relying on Amazon WorkSpaces for remote desktop infrastructure.
Amazon WorkSpaces is a desktop-as-a-service (DaaS) platform that provides virtual desktops in the cloud, allowing users to access applications and data securely from various devices.
The Linux client, in particular, is popular among enterprises with Linux-based workflows.
However, this vulnerability underscores the challenges in maintaining secure token management in multi-user environments.
Vulnerability Details
The vulnerability affects the Amazon WorkSpaces client for Linux versions 2023.0 through 2024.8.
It involves improper handling of authentication tokens specifically for DCV-based WorkSpaces (Desktop Cloud Visualization protocol).
Under certain circumstances, such as in shared or multi-user Linux systems, a local user with low privileges can extract another user's authentication token from the client machine.
Technically, the flaw is classified under CWE-497: Exposure of Sensitive System Information to an Unauthorized Control Sphere.
This means the client software fails to properly isolate authentication credentials, making them accessible via command-line access or system-level permissions on the same device.
Attackers do not require elevated privileges beyond local access, and no user interaction is needed, making the exploit relatively straightforward in vulnerable setups.
The National Vulnerability Database (NVD) rates this as a HIGH severity issue using CVSS 4.0, with high impacts on confidentiality, integrity, and availability.
Exploitability metrics indicate a local attack vector with low complexity, though it requires specific conditions (e.g., multiple users on the same machine).
Potential Impact and Risks
Once extracted, the authentication token allows an attacker to impersonate the victim, granting full access to their WorkSpace environment, including sensitive applications, data, and resources.
This could lead to data breaches, lateral movement within an organization's network, or further compromise of cloud resources.
The risks are particularly acute in environments where Linux machines are shared, such as development labs, educational institutions, or remote access kiosks.
Organizations with legacy deployments spanning the two-year exposure window (from 2023 onward) may face widespread vulnerabilities if updates have been neglected.
As one security analysis notes, "This vulnerability bypasses the authentication layer that separates individual Workspace sessions, potentially exposing sensitive business data and confidential user information to lateral movement attacks."
While no public exploits have been reported yet, the ease of access for local users makes this a pressing concern for multi-tenant systems.
Affected Systems and Discovery
The vulnerability exclusively impacts the Linux client for Amazon WorkSpaces using DCV protocol, not affecting Windows or other platforms.
It was disclosed by AWS itself, with no mention of external researchers in the bulletins.
AWS has proactively notified affected customers about the end-of-support for vulnerable versions, emphasizing their commitment to security.
Remediation and Best Practices
To mitigate the issue, AWS recommends immediately upgrading to the Amazon WorkSpaces client for Linux version 2025.0 or later.
The updated client can be downloaded from the official Amazon WorkSpaces Client Download page at https://clients.amazonworkspaces.com/.
Security teams should conduct inventory assessments to identify all deployed Linux clients and implement a phased upgrade strategy to minimize disruptions.
Additional advice includes:
- Avoiding shared Linux machines for WorkSpaces access where possible.
- Implementing strict user isolation and monitoring on multi-user systems.
- Establishing regular patch management cycles for remote access tools.
For any security-related questions, users can contact AWS at aws-security@amazon.com.
This CVE-2025-12779 serves as a reminder of the importance of secure credential handling in client-side applications, especially in cloud-based services like Amazon WorkSpaces.
By promptly updating to the fixed version, organizations can protect their remote work infrastructure from potential unauthorized access.
As remote and hybrid work models continue to evolve, staying vigilant with software updates remains a cornerstone of cybersecurity defense.
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Thanks for reading: Amazon WorkSpaces Linux Flaw Lets Attackers Steal Tokens, Sorry, my English is bad:)