Lightning Flow Scanner Vulnerable to Code Injection via Unsafe Use of new Function() in APIVersion Rule
Impact
The APIVersion rule uses new Function() to evaluate expression strings. A malicious crafted flow metadata file can cause arbitrary JavaScript execution during scanning. An attacker could execute arbitrary JavaScript during a scan by supplying a malicious expression within rule configuration or crafted flow metadata. This could compromise developer machines, CI runners, or editor environments.
Patches
The patch removes all uses of new Function() and replaces them with a safer parser. It now validates operators (>, >=, <, <=, ==`) and performs numeric comparisons without evaluating untrusted JavaScript.
version: core-v6.10.6,
version vsx:: v2.4.4
version app:: v3.1.0
Work around
```
// --- Handle APIVersion rule separately to avoid unsafe-eval in the core library ---
const apiVersionConfig = ruleConfig.rules.APIVersion;
if (apiVersionConfig) {
delete ruleConfig.rules.APIVersion;
}
// Manually evaluate the APIVersion rule, if it was configured.
if (apiVersionConfig) {
const flowApiVer = this.currentFlow.apiVersion || this.currentFlow.xmlData?.apiVersion;
const apiVersionRuleDef = allRules.find(r => r.name === "APIVersion");
// Determine the required expression (e.g. ">=58").
let requiredExpr;
if (apiVersionConfig.expression) {
requiredExpr = apiVersionConfig.expression;
} else if (apiVersionConfig.threshold != null) {
requiredExpr = >=${apiVersionConfig.threshold};
}
if (requiredExpr) {
const minVer = parseInt(requiredExpr.replace(/[^0-9]/g, ""), 10);
const operator = requiredExpr.replace(/[0-9]/g, "").trim();
const operators = {
">=": (a, b) => a < b,
"<": (a, b) => a >= b,
">": (a, b) => a <= b,
"<=": (a, b) => a > b,
"==": (a, b) => a !== b,
"=": (a, b) => a !== b
};
const violation = operators[operator] ? operators[operator](flowApiVer, minVer) : flowApiVer < minVer;
if (violation) {
// Craft a result object that mimics the core scanner output so downstream logic remains unchanged.
const manualScanResult = [{
flow: parsedFlow,
ruleResults: [{
ruleName: "APIVersion",
ruleDefinition: {
description: apiVersionRuleDef?.description || "API Version check",
label: apiVersionRuleDef?.label || "APIVersion"
},
occurs: true,
severity: apiVersionConfig.severity,
details: [{
name: String(flowApiVer),
type: "apiVersion",
expression: requiredExpr
}]
}]
}];
results.push(...this.processScanResults(manualScanResult));
}
}
}
```
