superjson: Improperly Controlled Modification of Object Prototype Attributes
CVE-2022-23631 is a critical-severity improperly controlled modification of object prototype attributes vulnerability in superjson from Blitz-js, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected superjson versions: < 1.8.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.68% chance of exploitation within 30 days, higher than 86% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Blitz to 0.45.3 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Blitz-js | superjson | < 1.8.0 | Not stated |
| Blitzjs | Blitz | before 0.45.3 | 0.45.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.0 | Critical | CNA (github.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 7.5 | High | NVD |
Official description
superjson is a program to allow JavaScript expressions to be serialized to a superset of JSON. In versions prior to 1.8.1 superjson allows input to run arbitrary code on any server using superjson input without prior authentication or knowledge. The only requirement is that the server implements at least one endpoint which uses superjson during request processing. This has been patched in superjson 1.8.1. Users are advised to update. There are no known workarounds for this issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improperly Controlled Modification of Object Prototype Attributes
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
How developers prevent this class of flaw
- By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
- By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
- When handling untrusted objects, validating using a schema can be used.
More Improperly Controlled Modification of Object Prototype Attributes vulnerabilities (CWE-1321)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/advisories/GHSA-5888-ffcr-r425Exploit, Third Party Advisory
- github.com/blitz-js/superjson/security/advisories/GHSA-5888-ffcr-r425Exploit, Third Party Advisory
Technical write-ups (may include proof of concept)
- sonarsource.com/blog/blitzjs-prototype-pollution/Exploit, Third Party Advisory
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