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GHSA-8h28-f46f-m87h

Insecure Deserialization in TYPO3 CMS

High Packagist
Severity
High
The publisher's own rating, not a CVSS score
Exploit chance (EPSS)
—
No score published
Known exploited
No
Not in CISA's catalog
Weakness
CWE-502 Deserialization of Untrusted Data
Fix
8.7.17
Upgrade typo3/cms to this version or later

Description

It has been discovered that the Form Framework (system extension "form") is vulnerable to Insecure Deserialization when being used with the additional PHP PECL package “yaml”, which is capable of unserializing YAML contents to PHP objects. A valid backend user account as well as having PHP setting "yaml.decode_php" enabled is needed to exploit this vulnerability (which is the default value according to PHP documentation).

Affected versions

Packagist

PackageVulnerableFixed in
typo3/cms
>= 8.5.0, < 8.7.17
8.7.17
typo3/cms
>= 9.0.0, < 9.3.2
9.3.2

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.

typo3/cms Packagist → 8.7.17

composer
composer require typo3/cms:^8.7.17

Weakness

CWE-502: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How to prevent it
  • Architecture and Design, Implementation: If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • Implementation: When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Implementation: Explicitly define a final object() to prevent deserialization.
  • Architecture and Design, Implementation: Make fields transient to protect them from deserialization. An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
  • Implementation: Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
  • Architecture and Design, Implementation: Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
  • Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Timeline

  1. Published
  2. Last updated by the source
AdvisorySeverityWhy it's related
GHSA-f3wf-q4fj-3gxf
TYPO3 Denial of Service in Online Media Asset Handling
Medium Also affects typo3/cms
GHSA-6487-3qvg-8px9
TYPO3 Information Disclosure in Install Tool
Medium Also affects typo3/cms
GHSA-f777-f784-36gm
TYPO3 Security Misconfiguration in Install Tool Cookie
High Also affects typo3/cms
GHSA-2rcw-9hrm-8q7q
TYPO3 Cross-Site Scripting in Frontend User Login
Medium Also affects typo3/cms
GHSA-7q33-hxwj-7p8v
TYPO3 Cross-Site Scripting in Backend Modal Component
Medium Also affects typo3/cms
GHSA-8m6j-p5jv-v69w
TYPO3 Cross-Site Scripting in Online Media Asset Rendering
Medium Also affects typo3/cms
GHSA-8h4m-r4wm-xj7r
TYPO3 Arbitrary Code Execution via File List Module
High Also affects typo3/cms
GHSA-g585-crjf-vhwq
TYPO3 Denial of Service in Frontend Record Registration
High Also affects typo3/cms
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