CVE-2016-3115
Description
It was discovered that the OpenSSH server did not sanitize data received in requests to enable X11 forwarding. An authenticated client with restricted SSH access could possibly use this flaw to bypass intended restrictions.
Mitigation
Set X11Forwarding=no in sshd_config.
For authorized_keys that specify a "command" restriction, this issue can be mitigated by also setting the "no-X11-forwarding" restriction. In OpenSSH 7.2 and later, the "restrict" restriction can be used instead, which includes the "no-X11-forwarding" restriction.
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 v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.9 | 5.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | Single | Single | N/A |
| Confidentiality Impact | Partial | Partial | N/A |
| Integrity Impact | Partial | Partial | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: AV:N/AC:M/Au:S/C:P/I:P/A:N
NVD: AV:N/AC:L/Au:S/C:P/I:P/A:N
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.
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