Summary
The lack of sanitization of URLs protocols in the createLink.openLink function enables the execution of arbitrary JavaScript code within the context of the parent page.
Details
https://github.com/FrontFin/mesh-web-sdk/blob/cf013b85ab95d64c63cbe46d6cb14695474924e7/packages/link/src/Link.ts#L441
The createLink.openLink function takes base64 encoded links, decodes them, and then sets the resulting string as the src attribute of an iframe. It’s important to note that the protocol part is not validated, so a payload, which is a valid URL, such as javascript:alert(document.domain)//, can be provided to the function.
PoC
- Extract poc-mesh-web-sdk.zip
- Run
yarn install and then yarn start
- Paste this payload inside the input box:
amF2YXNjcmlwdDphbGVydCh3aW5kb3cucGFyZW50LmRvY3VtZW50LmJvZHkuZ2V0RWxlbWVudHNCeVRhZ05hbWUoImgyIikuaXRlbSgwKVsiaW5uZXJIVE1MIl0pLy8=
- Click on the OpenLink button
- Notice the alert box and ability to access the
h2 title from the parent page
It can also be verified via https://paylink.meshconnect.com/?linkToken=amF2YXNjcmlwdDphbGVydCgpLy8=.
Impact
This is technically indistinguishable from a real page at the rendering level and allows access to the parent page DOM, storage, session, and cookies. If the attacker can specify customIframeId, they can hijack the source of existing iframes.
If access to the private key is possible or if transactions are tampered with or initialized, in a wallet context, it can result in a critical impact due to loss of funds scenarios.
Reporters
References
aptos-security Sponsor
zwxxb Finder
zi0Black Reporter
Summary
The lack of sanitization of URLs protocols in the
createLink.openLinkfunction enables the execution of arbitrary JavaScript code within the context of the parent page.Details
https://github.com/FrontFin/mesh-web-sdk/blob/cf013b85ab95d64c63cbe46d6cb14695474924e7/packages/link/src/Link.ts#L441
The
createLink.openLinkfunction takes base64 encoded links, decodes them, and then sets the resulting string as thesrcattribute of aniframe. It’s important to note that the protocol part is not validated, so a payload, which is a valid URL, such asjavascript:alert(document.domain)//, can be provided to the function.PoC
yarn installand thenyarn startamF2YXNjcmlwdDphbGVydCh3aW5kb3cucGFyZW50LmRvY3VtZW50LmJvZHkuZ2V0RWxlbWVudHNCeVRhZ05hbWUoImgyIikuaXRlbSgwKVsiaW5uZXJIVE1MIl0pLy8=h2title from the parent pageIt can also be verified via
https://paylink.meshconnect.com/?linkToken=amF2YXNjcmlwdDphbGVydCgpLy8=.Impact
This is technically indistinguishable from a real page at the rendering level and allows access to the parent page DOM, storage, session, and cookies. If the attacker can specify
customIframeId, they can hijack the source of existing iframes.If access to the private key is possible or if transactions are tampered with or initialized, in a wallet context, it can result in a critical impact due to loss of funds scenarios.
Reporters
zwxxbElsassi of Aptos LabsReferences