CVE-2021-21305 Vulnerability Analysis & Exploit Details

CVE-2021-21305
Vulnerability Scoring

7.4
/10
Very High Risk

Highly exploitable, CVE-2021-21305 poses a critical security risk that could lead to severe breaches.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: Low
    Some privileges are necessary to exploit the vulnerability.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-21305 Details

Status: Modified

Last updated: 🕠 21 Nov 2024, 05:47 UTC
Originally published on: 🕗 08 Feb 2021, 20:15 UTC

Time between publication and last update: 1381 days

CVSS Release: version 3

CVSS3 Source

security-advisories@github.com

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

CVE-2021-21305 Vulnerability Summary

CVE-2021-21305: CarrierWave is an open-source RubyGem which provides a simple and flexible way to upload files from Ruby applications. In CarrierWave before versions 1.3.2 and 2.1.1, there is a code injection vulnerability. The "#manipulate!" method inappropriately evals the content of mutation option(:read/:write), allowing attackers to craft a string that can be executed as a Ruby code. If an application developer supplies untrusted inputs to the option, it will lead to remote code execution(RCE). This is fixed in versions 1.3.2 and 2.1.1.

Assessing the Risk of CVE-2021-21305

Access Complexity Graph

The exploitability of CVE-2021-21305 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2021-21305

CVE-2021-21305 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2021-21305, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2021-21305, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: Low
    CVE-2021-21305 could lead to minor leaks of non-critical information without major privacy breaches.
  • Integrity: Low
    Exploiting CVE-2021-21305 may cause minor changes to data without severely impacting its accuracy.
  • Availability: Low
    CVE-2021-21305 may slightly degrade system performance without fully affecting service availability.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 1.141% (probability of exploit)

EPSS Percentile: 84.95% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 15.049999999999997% of others.

CVE-2021-21305 References

External References

CWE Common Weakness Enumeration

CWE-94

CAPEC Common Attack Pattern Enumeration and Classification

  • Code Injection CAPEC-242 An adversary exploits a weakness in input validation on the target to inject new code into that which is currently executing. This differs from code inclusion in that code inclusion involves the addition or replacement of a reference to a code file, which is subsequently loaded by the target and used as part of the code of some application.
  • Leverage Executable Code in Non-Executable Files CAPEC-35 An attack of this type exploits a system's trust in configuration and resource files. When the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high.
  • Manipulating User-Controlled Variables CAPEC-77 This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.

Vulnerable Configurations

  • cpe:2.3:a:carrierwave_project:carrierwave:0.1.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.1.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.2.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.2.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.2.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.2.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.2.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.2.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.2.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.2.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.5:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.5:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.5.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.5.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.3.5.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.3.5.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.5:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.5:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.6:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.6:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.7:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.7:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.8:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.8:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.9:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.9:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.4.10:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.4.10:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.0:-:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.0:-:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.0:beta2:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.0:beta2:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.5:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.5:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.6:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.6:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.7:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.7:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.5.8:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.5.8:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.6.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.6.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.6.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.6.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.6.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.6.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.7.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.7.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.7.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.7.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.8.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.8.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.9.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.9.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.10.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.10.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.11.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.11.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.11.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.11.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:0.11.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:0.11.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:-:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:-:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:rc:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:rc:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:beta:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.0.0:beta:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.1.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.1.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.2.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.2.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.2.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.2.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.2.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.2.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.2.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.2.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.3.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.3.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:1.3.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:1.3.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:2.0.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:2.0.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:2.0.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:2.0.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:carrierwave_project:carrierwave:2.1.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:carrierwave_project:carrierwave:2.1.0:*:*:*:*:ruby:*:*

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