January 23, 2017

Google discloses three more zero-day vulnerabilities, this time for OS X

Apple-logo(LiveHacking.Com) – Google recently came under some heavy criticism when it disclosed a zero-day vulnerability in Windows just days before Microsoft was scheduled to release a fix. Now the search giant as done it again. But this time Google shows that it is truly non-partisan because the disclosures aren’t for Windows, but for OS X.

The first vulnerability allows an attacker to pass arbitrary commands to the networkd OS X system daemon in XPC  messages. XPC provides a lightweight mechanism for basic interprocess communication. The problem is that the daemon uses the values from  xpc_dictionary_get_value and xpc_array_get_value without subsequent checking of the type of the returned value. Google posted proof-of-concept (POC) code that allows a shell command to be executed as networkd on OS X 10.9.5. The POC uses a specially crafted XPC message which results in “touch /tmp/hello_networkd” being executed. That is a benign command, but it can be replaced with something more malicious.

The second vulnerability in IOKit IOService allows an attacker to  execute code on an OS X machine with root privileges through a null pointer dereferencing. The third flaws also relates to IOKit, this time in the Bluetooth subsystem. To exploit it the machine needs to have a Bluetooth device attached, for example a Apple Bluetooth keyboard. Once exploited it allows an attacker to write into kernel memory, potentially allowing them to create a denial of service situation or to access private data.

The security flaws were reported to Apple in October 2014. All three advisories were subsequently published by Google after the expiration of the 90-day grace period give under Project Zero.

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