CVE-2016-0752
Description
A directory traversal flaw was found in the way the Action View component searched for templates for rendering. If an application passed untrusted input to the 'render' method, a remote, unauthenticated attacker could use this flaw to render unexpected files and, possibly, execute arbitrary code.
Mitigation
Avoid passing untrusted input to render method, or verify the input using whitelist before passing it to the render method:
def index
render verify_template(params[:id])
end
private
def verify_template(name)
# add verification logic particular to your application here
end
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 | 6.8 | 5 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Partial | Partial | N/A |
| Integrity Impact | Partial | None | N/A |
| Availability Impact | Partial | None | N/A |
Vector
Red Hat: AV:N/AC:M/Au:N/C:P/I:P/A:P
NVD: AV:N/AC:L/Au:N/C:P/I:N/A:N
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity
Technical Impact: Modify Files or Directories
The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality
Technical Impact: Read Files or Directories
The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.
Acknowledgements
Red Hat would like to thank the Ruby on Rails project for reporting this issue. Upstream acknowledges John Poulin as the original reporter.
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