CVE-2022-48565
Description
A flaw was found in Python caused by improper handling of XML external entity (XXE) declarations by the plistlib module. By using a specially crafted XML content, an attacker could obtain sensitive information by disclosing files specified by parsing URI, and may cause denial of service by resource exhaustion.
Statement
This vulnerability is classified as Moderate according to Red Hat's Severity Rating Classification, as in contrast to an Important severity rating, the conditions to exploit this vulnerability makes it highly improbable for a general remote use case to lead to arbitrary code execution or affect data integrity and the highest impact is data disclosure and application crash.
The versions of python as shipped with Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 9 either has fixed code or they just provide symlinks to the main python3 component, which provides the interpreter of the Python programming language. Therefore, both Red Hat Enterprise Linux versions 8 and 9 are not affected.
Mitigation
The XML modules in python are not secure against erroneous or maliciously constructed data. If you need to parse untrusted or unauthenticated data, see the XML vulnerabilities and the defusedxml package sections.
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 | 7.8 | 9.8 | N/A |
| Attack Vector | Local | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | None | N/A |
| User Interaction | None | None | 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
This vulnerability can only be exploited by parsing a vulnerable .plist file, which is why attack vector has been marked as local.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system. By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g., in an error message), thereby exposing the file contents.
Integrity
Technical Impact: Bypass Protection Mechanism
An attacker may supply a crafted DTD using URIs with schemes such as http://, forcing the application to make outgoing HTTP requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions; hide the source of attacks such as port scanning; or otherwise leverage the server's trust relationship with other entities.
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
The product could consume excessive CPU cycles or memory using a URI that points to a large file, or a device that always returns data such as /dev/random. Alternately, the URI could reference a file that contains many nested or recursive entity references to further slow down parsing.
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