CVE-2019-0211
Description
A flaw was found in Apache where code executing in a less-privileged child process or thread could execute arbitrary code with the privilege of the parent process (usually root). An attacker having access to run arbitrary scripts on the web server (PHP, CGI etc) could use this flaw to run code on the web server with root privileges.
Statement
This flaw is exploitable in httpd if it is configured to allow an untrusted user to upload and execute arbitrary scripts. Due to the nature of the flaw, the uploaded script would not run as a restricted privileged user, but rather it runs as root allowing for privilege escalation from the restricted user to root on the web server.
Depending on the configuration of the server, you would need local (AV:L) privileges to place the script or network (AV:N) privileges if the server ran an application that permitted uploading scripts directly. The latter scenario is not common for unauthenticated users. Once the attacker can place the script somewhere in the web root where it can be easily exploited (AC:L). This type of setup is more common in shared hosted environments (PR:L) and would allow an attacker with access to a site on the shared hosted to impact the confidentiality, integrity, and availability (CIA:H) with no interaction (UI:N). Due to the elevated privileges obtained, there is an impact to the system beyond the web server itself (S:C).
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 | 8.8 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Changed | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Access Control
Technical Impact: Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands; Read Application Data; DoS: Crash, Exit, or Restart
An attacker will be able to gain access to any resources that are allowed by the extra privileges. Common results include executing code, disabling services, and reading restricted data. New weaknesses can be exposed because running with extra privileges, such as root or Administrator, can disable the normal security checks being performed by the operating system or surrounding environment. Other pre-existing weaknesses can turn into security vulnerabilities if they occur while operating at raised privileges.
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