Google on Thursday pushed out an over the air update to its Nexus devices to fix the notorious Stagefright bug, but it's confirmed to CSO Australia that a complete fix won’t come until September.
Just days after Google, Samsung and HTC promised to speed up security patches for Android and released fixes for some devices affected by the Stagefright bug, security firm Exodus Intelligence says the fix that’s currently going out doesn’t entirely resolve the problem.
Stagefright affected all Android devices above Android 2.2, which amounted to an estimated 950 million devices. The bug was seen as particularly dangerous since exploitation only required a malicious MMS to be received by a vulnerable device.
Google released factory images for Nexus devices that included fixes for the bugs affecting Stagefright last week and todayreleased that same update over the air (OTA) to its line of Nexus devices.
However, Exodus Intelligence today said that even with the updated firmware, a Nexus 5 could still be exploited by receiving a specially crafted MP4 file. It made the somewhat controversial decision to reveal details of the lingering bug on Thursday despite the absence of a deployed patch.
While most Android users won’t benefit from Google’s response to the disclosure, the company did on Thursday release an open source patch that addresses the flaw.
A Google spokesperson told CSO Australia that the issue would be fixed in September in its Nexus devices, and that risk is minimised in of 90 percent of Android devices due to their having the anti-exploitation feature Address Space Layout Randomisation (ASLR) enabled.
“We’ve already sent the fix to our partners to protect users, and Nexus 4/5/6/7/9/10 and Nexus Player will get the OTA update in the September monthly security update,” the spokesperson said.
Joshua Drake, the security researcher that reported the Stagefright bugs — named so because they were located in a media library called Stagefright — said he had developed an proof of concept exploit for the newly reported bug.
Google has assigned the bug the official identifier CVE-2015-3864.
Exodus Intelligence said it had used Google’s factory images to test a hunch that a patch (CVE-2015-3824) — that Drake had provided to Google — “suffered from a severe problem”.
“We notified Google of the issue on August 7th but have not had a reply to our query regarding their release of an updated fix. Due to this, as well as the following facts, we have decided to notify the public of our findings,” Exodus Intelligence said.
Exodus Intelligence justified its decision to disclose details of the bug on the basis that Google was aware of its report but continued to distribute a “faulty patch” to Android devices.
“Google has not given us any indication of a timeline for correcting the faulty patch, despite our queries,” the company said.
“There has been an inordinate amount of attention drawn to the bug. We believe we are likely not the only ones to have noticed it is flawed. Others may have malicious intentions.”
Want to know more?
Why not become a CSO member and subscribe to CSO's mailing list.
Get newsletters, updates, events and more right here