GHSA-5h5v-m596-r6rf
TYPO3 Possible Insecure Deserialization in Extbase Request Handling
- Severity
- 8.1 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-502 Deserialization of Untrusted Data
- Fix
8.7.30- Upgrade typo3/cms-core to this version or later
Description
It has been discovered that request handling in Extbase can be vulnerable to insecure deserialization. User submitted payload has to be signed with a corresponding HMAC-SHA1 using the sensitive TYPO3 encryptionKey as secret - invalid or unsigned payload is not deserialized.
However, since sensitive information could have been leaked by accident (e.g. in repositories or in commonly known and unprotected backup files), there is the possibility that attackers know the private encryptionKey and are able to calculate the required HMAC-SHA1 to allow a malicious payload to be deserialized.
Requirements for successfully exploiting this vulnerability (all of the following):
- rendering at least one Extbase plugin in the frontend
- encryptionKey has been leaked (from LocalConfiguration.php or corresponding .env file)
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| typo3/cms-core | >= 8.0.0, < 8.7.30 |
8.7.30 |
| typo3/cms-core | >= 9.0.0, < 9.5.12 |
9.5.12 |
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-core Packagist → 8.7.30
- composer
composer require typo3/cms-core:^8.7.30
Severity breakdown
CVSS 3.1 8.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
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
Packages
Other links
Timeline
- Published
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-68jx-f42c-7599 TYPO3 CMS - Broken Access Control in Backend and Install Tool | High | Also affects typo3/cms-core |
| GHSA-chm7-4vch-h8vr TYPO3 CMS has Broken Access Control in its Media Module | High | Also affects typo3/cms-core |
| GHSA-jh32-v29g-68pq TYPO3 CMS has Privilege Escalation & SQL Injection in its Form Framework | High | Also affects typo3/cms-core |
| GHSA-c78m-c52x-jgwp TYPO3 CMS has Insecure Deserialization via Core API | Medium | Also affects typo3/cms-core |
| GHSA-jf56-v8jc-jcc5 TYPO3 CMS has Broken Access Control in its File Abstraction Layer | Low | Also affects typo3/cms-core |
| GHSA-2j54-93q2-3hjq TYPO3 CMS has Broken Access Control in Backend API | Medium | Also affects typo3/cms-core |
| GHSA-q93m-25xv-94hh TYPO3 CMS: Broken Access Control in Media Module | Medium | Also affects typo3/cms-core |
| GHSA-qcmw-6rm2-5x78 TYPO3 CMS has Broken Access Control in its DataHandler | Medium | Also affects typo3/cms-core |
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