CVE-2021-23961:

Firefox Slipstream Vulnerability Exposing Internal Network and Local Services

Score
A numerical rating that indicates how dangerous this vulnerability is.

7.4High

Published Date:Feb 26, 2021
CISA KEV Date:*No Data*
Industries Affected:20

Threat Predictions

EPSS Score:0.6
EPSS Percentile:70%

Exploitability

Score:2.8
Attack Vector:NETWORK
Attack Complexity:LOW
Privileges Required:NONE
User Interaction:REQUIRED
Scope:CHANGED

Impact

Score:4.0
Confidentiality Impact:HIGH
Integrity Impact:NONE
Availability Impact:NONE

Description Preview

Firefox Slipstream Vulnerability Exposing Internal Network and Local Services

Overview

This vulnerability is related to the slipstream research, which demonstrated techniques for bypassing browser-based network protections. In Firefox versions before 85, a malicious webpage could leverage enhanced slipstream techniques to perform network scanning that could reveal: 1. Internal network hosts that should be hidden from external websites 2. Services running on the user's local machine 3. Potentially sensitive information about the network topology The attack requires a user to visit a specially crafted malicious webpage, which then executes code that probes the internal network or local services. This could lead to information disclosure and potentially serve as reconnaissance for further attacks.

Remediation

To address this vulnerability, users and administrators should:
1. Update Firefox to version 85 or later, which contains patches that mitigate this vulnerability
2. Ensure automatic updates are enabled for Firefox installations
3. For enterprise environments, deploy the updated Firefox version through your standard software deployment mechanisms
4. Consider implementing additional network segmentation to reduce the impact of similar browser-based attacks
5. For Debian users, apply the security updates referenced in DSA-4895, DSA-4897, or DLA-2632-1, DLA-2633-1 as appropriate
6. For Gentoo users, follow the guidance in GLSA-202104-09 and GLSA-202104-10