Phpfox: Deserialization of Untrusted Data
CVE-2023-46817 is a critical-severity deserialization of untrusted data vulnerability in Phpfox, 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. The record lists version 4.8.13 as the first without the flaw, so updating Phpfox to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.33% chance of exploitation within 30 days, higher than 84% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Phpfox to 4.8.13 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. 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 | 9.8 | Critical | NVD |
| CVSS 3.1 | 9.8 | Critical | CISA (ADP) |
Official description
An issue was discovered in phpFox before 4.8.14. The url request parameter passed to the /core/redirect route is not properly sanitized before being used in a call to the unserialize() PHP function. This can be exploited by remote, unauthenticated attackers to inject arbitrary PHP objects into the application scope, allowing them to perform a variety of attacks, such as executing arbitrary PHP code.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- 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.
- 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.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- karmainsecurity.com/KIS-2023-12Third Party Advisory
Technical write-ups (may include proof of concept)
- seclists.org/fulldisclosure/2023/Oct/30Exploit, Mailing List, Third Party Advisory
- karmainsecurity.com/pocs/CVE-2023-46817.phpExploit, Third Party Advisory
Other references
Other vulnerabilities in Phpfox
- 7.1 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 9.8 Critical severity
- 8.1 High severity
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