CVE-2020-23793
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Description
A flaw was found in spice-server in Redhat's VDI product that can restart KVMvirtual machine without any authorization. A handshake is required before spice-server and spice-client can establish communication, and spice-client will send a request containing information that the server needs. This TCP request requires only host and port; A malformed TCP packet causes the vm to crash and the QEMu-KVM process to be restarted.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Additional information
- Bugzilla 2234984: spice: Improper input validation in function async_READ_handler
- CWE-20: Improper Input Validation
- FAQ: Frequently asked questions about CVE-2020-23793
Common Vulnerability Scoring System (CVSS) Score Details
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.
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 7.4 | N/A |
Attack Vector | Adjacent Network | N/A |
Attack Complexity | Low | N/A |
Privileges Required | None | N/A |
User Interaction | None | N/A |
Scope | Changed | N/A |
Confidentiality Impact | None | N/A |
Integrity Impact | None | N/A |
Availability Impact | High | N/A |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
The affected component is connected to the network stack, but the attack is limited at the protocol level to a logically adjacent topology.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
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