Skip to content
Log inStart free trial

GHSA-cf3w-g86h-35x4 CVE-2021-21305

Code Injection vulnerability in CarrierWave::RMagick

High RubyGems
Severity
7.4 / 10
High · CVSS 3.1
Exploit chance (EPSS)
12.68%
Chance of exploitation in the next 30 days. Higher than 96.26% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-94 Improper Control of Generation of Code ('Code Injection')
Fix
1.3.2
Upgrade carrierwave to this version or later

Description

Impact

CarrierWave::RMagick has a Code Injection vulnerability. Its #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).

(But supplying untrusted input to the option itself is dangerous even in absence of this vulnerability, since is prone to DoS vulnerability - attackers can try to consume massive amounts of memory by resizing to a very large dimension)

Proof of Concept

class MyUploader < CarrierWave::Uploader::Base
  include CarrierWave::RMagick
end

MyUploader.new.manipulate!({ read: { density: "1 }; p 'Hacked'; {" }}) # => shows "Hacked"

Patches

Upgrade to 2.1.1 or 1.3.2.

Workarounds

Stop supplying untrusted input to #manipulate!'s mutation option.

References

Code Injection Software Attack

For more information

If you have any questions or comments about this advisory:

Affected versions

RubyGems

PackageVulnerableFixed in
carrierwave
< 1.3.2
1.3.2
carrierwave
>= 2.0.0, < 2.1.1
2.1.1

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

carrierwave RubyGems → 1.3.2

bundler
bundle update carrierwave # Gemfile: gem "carrierwave", ">= 1.3.2"

Severity breakdown

CVSS 3.1 7.4

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

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

Weakness

CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

How to prevent it
  • Requirements: Programming languages and supporting technologies might be chosen which are not subject to these issues.
  • Implementation: Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.

CWE-94: Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

How to prevent it
  • Architecture and Design: Refactor your program so that you do not have to dynamically generate code.
  • Architecture and Design: Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().
  • Testing: Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
  • Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
  • Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
  • Implementation: For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].

References

Advisories

Packages

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-7g26-2qgj-chfg
CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters
Medium Also affects carrierwave
GHSA-vfmv-jfc5-pjjw
CarrierWave content-Type allowlist bypass vulnerability which possibly leads to XSS remained
Medium Also affects carrierwave
GHSA-gxhx-g4fq-49hj
CarrierWave Content-Type allowlist bypass vulnerability, possibly leading to XSS
Medium Also affects carrierwave
GHSA-fwcm-636p-68r5
Server-side request forgery in CarrierWave
Medium Also affects carrierwave
GHSA-j8rh-479h-cp32
Axios: Header Injection via Inherited headers After Minimal Interceptor
Medium Same weakness, CWE-74
GHSA-4hqw-qxg8-jxx2
Axios: Fetch Adapter Header Injection via Inherited FormData getHeaders
Medium Same weakness, CWE-74
GHSA-h58c-xccx-75m3
Coder: Stored HTML injection via unescaped ApplicationName and LogoURL appearance settings
Medium Same weakness, CWE-74
GHSA-5rw4-4665-cvwf
Froxlor DomainZones.add allows DNS zone-file RR injection via record/type fields
Medium Same weakness, CWE-74
Is this in your code?

MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.

Check your repos with MergeHarbor