CVE-2021-28041
Description
A double-free memory corruption flaw was found in OpenSSH 8.2, more specifically in ssh-agent application. This flaw allows an attacker with access to the agent socket to forward an agent either to an account shared with a malicious user or to a host with an attacker holding root access. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
Statement
This issue doesn't affected any versions of OpenSSH packaged and shipped with Red Hat Enterprise Linux 6, 7 and 8. The issue was introduced in OpenSSH 8.2 while the most recent OpenSSH version available for Red Hat Enterprise Linux 8 is based on OpenSSH 8.0.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.1 | 7.1 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
Exploitation of this vulnerability requires access to the ssh-agent socket, which by default is accessible only to the user that invokes ssh-agent. Thus, the user must take an active step (UI:R) to share the socket with an untrusted user, or an untrusted remote host to which they are connecting with ssh -A. If neither of these occurs, the user is not exposed (AC:H). In either case, the attacker must have sufficient privileges to access the socket (PR:L).
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