# Hardening Valet Against an OS X Keychain Access Control List Vulnerability

DevFeed: [Hardening Valet Against an OS X Keychain Access Control List Vulnerability](<https://devfeed.tech/articles/valet-beats-the-os-x-keychain-access-control-list-zero-day-vulnerability-15946.md>)

Original publisher: [Read original article](<https://developer.squareup.com/blog/valet-beats-the-os-x-keychain-access-control-list-zero-day-vulnerability>)

Author: Square Engineering

Published: 2016-06-19T16:12:00Z

Content type: article

Language: en

Sources: [Square Corner Blog RSS Feed](<https://devfeed.tech/sources/square-corner-blog-rss-feed.md>)

Topics: [Test-driven development](<https://devfeed.tech/topics/tdd.md>), [Security](<https://devfeed.tech/topics/security.md>), [Access Control](<https://devfeed.tech/topics/access-control.md>), [cross-platform](<https://devfeed.tech/topics/cross-platform.md>), [iOS](<https://devfeed.tech/topics/ios.md>)

Tags: [access-control](<https://devfeed.tech/tags/access-control.md>), [code](<https://devfeed.tech/tags/code.md>), [cross-platform](<https://devfeed.tech/tags/cross-platform.md>), [development](<https://devfeed.tech/tags/development.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [ios](<https://devfeed.tech/tags/ios.md>), [security](<https://devfeed.tech/tags/security.md>), [test](<https://devfeed.tech/tags/test.md>), [vulnerability](<https://devfeed.tech/tags/vulnerability.md>)

## AI overview

The article explains how Square investigated a reported Keychain attack, identified a vulnerability in Valet's OS X component, and hardened it by deleting and re-adding keychain entries instead of updating them.

## Source excerpt

How we used test driven development to replicate an attack vector and harden our code against it