CVE-2021-3688
Description
A flaw was found in Red Hat JBoss Core Services HTTP Server in all versions, where it does not properly normalize the path component of a request URL contains dot-dot-semicolon(s). This flaw could allow an attacker to access unauthorized information or possibly conduct further attacks. The highest threat from this vulnerability is to data confidentiality and integrity.
Mitigation
Manually add LocationMatch directive to deny any possible problem requests in the JBCS httpd configuration. For example:
<LocationMatch ".*\.\.;.*">
Require all denied
</LocationMatch>
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.8 | 4.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Red Hat CVSS v3 Score Explanation
AC:H, because mod_proxy and mod_cluster are NOT the default configuration and the vulnerability can be exploited only if the attacker knows what path is deployed on the app server. These conditions can be the "under certain circumstances" which are beyond attacker's control.
C:L and I:L, because the bug is related to a user who is running the servers. The leak/modification is limited to a user's authority in the OS. An attacker can't get everything of the system and cannot have control over the information.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Frequently Asked Questions
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