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Wasmer filesystem sandbox not enforced

High severity GitHub Reviewed Published Dec 12, 2023 in wasmerio/wasmer • Updated Jan 3, 2024

Package

cargo wasmer-cli (Rust)

Affected versions

>= 3.0.0, < 4.2.4

Patched versions

4.2.4

Description

Summary

As of Wasmer version v4.2.3, Wasm programs can access the filesystem outside of the sandbox.

Details

wasmerio/wasmer#4267

PoC

A minimal Rust program:

fn main() {
    let f = std::fs::OpenOptions::new()
        .write(true)
        .create_new(true)
        .open("abc")
        .unwrap();
}

This should be compiled with cargo build --target wasm32-wasi. The compiled program, when run with wasmer WITHOUT --dir, can still create a file in the working directory.

Impact

Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem.

References

@syrusakbary syrusakbary published to wasmerio/wasmer Dec 12, 2023
Published to the GitHub Advisory Database Dec 13, 2023
Reviewed Dec 13, 2023
Published by the National Vulnerability Database Dec 22, 2023
Last updated Jan 3, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.081%
(37th percentile)

Weaknesses

CVE ID

CVE-2023-51661

GHSA ID

GHSA-4mq4-7rw3-vm5j

Source code

Credits

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