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Posts tagged ‘javascript’

10
Mar

Safari Errorjacking Vulnerability and Exploit [Patched]

One of the vulnerabilities patched in Safari 5.0.4 is a fairly critical issue in WebKit (CVE-2011-0167) that allows Javascript to jump into the local zone, and access any file on the local computer that is accessible to the current user. This could be used by malicious websites to extract files and information from the victim’s computer. The vulnerability affects Safari on Mac OS X and Windows, and could affect other WebKit-based browsers, although Chrome is safe due to added restrictions.

The bug exists because most browser error pages are loaded from the local “file:” zone, a zone that Javascript is not normally allowed to access directly. Since a child browser window remains under the control of the parent, it is possible to cause a child browser window to error, thus entering the normally-restricted local zone, and then instructing the child window to access local files using this elevated local-zone privilege.

This issue was a nice catch, discovered by Aaron Sigel who has a detailed explanation, video demo and proof-of-concept on his blog. It probably goes without saying, but Safari users should run Software Update as soon as possible.

26
Nov

Ravan: Distributed Hash Cracking in JavaScript

The guys over at Attack & Defence Labs have released Ravan, a distributed hash cracker the runs in JavaScript. Users can submit hashes to be cracked, and their browser will then begin brute forcing them based on a user-defined charset. Other users can contribute some CPU power to assist in the cracking process of individual hashes, it’s all handled by the server. This would work particularly well if you have multiple computers, or lots of friends willing to help out in the cracking process. Note that as this is brute force and not dictionary-based, it really comes down to how many hashes per second are being tried.

Current supported hash algorithms are MD5, SHA-1, SHA-256 and SHA-512.

8
Nov

Clever Full-Site Tracking with XSS-Track

Cross-site Scripting (or XSS) is a common web application vulnerability with varying levels of severity. Generally the capabilities of a XSS are limited to the locations of vulnerable inputs and outputs, and crafting complex XSS payloads can be a time-consuming process.

XSS-Track (cached) helps simplify cross-site scripting by allowing the attacker to silently track the user across the entire site, using a single embedded XSS. It does this by cleverly creating a full-window invisible iFrame, and maintaining control of that window as the user browses the site. This also allows the attacker to look for valuable pieces of information, such as passwords or credit card numbers.

Combining XSS-Track with the older XSS-Shell script, which turns the browser into a zombie of sorts, could give an attacker a significant amount of power over infected sites and their users.

Firefox users may want to consider using the NoScript extension to protect themselves from unknowingly running malicious scripts. Despite having some limited XSS protection, and a JavaScript Blacklist extension, Safari unfortunately does not afford nearly the same protection as the whitelist-style Firefox+NoScript combination. If someone releases a NoScript-style JS Whitelist for Safari then it’ll be a big step forward.

19
Aug

Hack Uses Geolocation to Pinpoint Your Location

In one of the more simple yet clever attacks I’ve seen this year, at BlackHat and Defcon, Samy Kamkar (author of the 2005 Samy MySpace worm) showed how javascript and geolocation could be used to more or less pinpoint a user’s location. An attack Samy dubbed ‘XXXSS‘.

The attack works by using javascript to obtain the MAC address (a unique hardware identifier) of the victim’s network router or gateway, and then submitting it to Google’s Geolocation service to obtain the coordinates. Read moreRead more

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