Horizon Alert
Summary of the vulnerability and why it matters
A critical vulnerability in the YesWiki system could allow for server crashes or complete system compromise. The issue stems from how the system processes mathematical formulas in its form fields, potentially enabling attackers to execute arbitrary code on the server. The main concern is confirming relevance and exposure, as this could have significant implications if YesWiki is in use.
- Unsafe math formula processing could risk server control.
- Critical vulnerability impacts a widely used wiki system.
- Confirm YesWiki usage and assess exposure immediately.
Attack Path
How an attacker could exploit the issue
An attacker could exploit this vulnerability by sending a specially crafted mathematical formula to the YesWiki system through its form field calculator. Because the application's sanitization process for these formulas is flawed and does not properly prevent malicious input from reaching the PHP eval() function, an attacker could bypass security checks. Successful exploitation can lead to arbitrary PHP code execution on the server, giving the attacker significant control.
- No special access required.
- Submit malicious formula to calculator.
- Arbitrary code execution.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability in YesWiki's form field calculator could allow an unauthenticated attacker to execute arbitrary PHP code on the server when supported by the advisory. This occurs because user-supplied mathematical formulas are not adequately sanitized before being processed by the PHP `eval()` function, creating an insecure execution environment.
- Arbitrary PHP code execution.
- Unsanitized user input to `eval()`.
- Server compromise and data theft.
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability impacts YesWiki instances, likely managed by web administrators or platform teams responsible for the wiki system. The immediate priority is to identify all deployed YesWiki instances, determine their exposure, and confirm business criticality. This will inform the prioritization of remediation efforts, which may involve coordination with the vendor or development teams for applying updates within planned maintenance windows.
- Confirm YesWiki instances and their exposure.
- Identify accountable owners for each instance.
- Plan remediation based on risk assessment.
