US spy agency issues damage-controlling Android

The United States National Security Agency (NSA) has released a security-hardened version of Android, designed to cut down the litany of security risks affecting the mobile operating system.

The Security Enhanced (SE) Android system is based on the NSA-developed SELinux feature.

It was first flagged by the spy agency last year as a means to prevent damage from malicious or vulnerable applicatons.

"Initially, the SEAndroid project is enabling the use of SELinux in Android in order to limit the damage that can be done by flawed or malicious apps and in order to enforce separation guarantees between apps," the NSA said on its website for the project.

Specifically, SEAndroid can: confine and protect privileged daemons; sandbox and accurately isolate applications and prevent privilege escalation; and introduce a centralised policy.

It generally cannot prevent Kernel vulnerabilities but can, in some instances, prevent exploitation.

At the Linux Security Conference last year, NSA developer Stephen Smalley demonstrated how SEAndroid would defeat a string of previously successful Android root exploits including GingerBreak, RageAgainstTheCage, and ueventd.

The NSA released SEAndroid source code for the first time earlier this month.

According to the project website, new features in the the hardened SEAndroid platform include:

• Per-file security labeling support for yaffs2,
• Filesystem images (yaffs2 and ext4) labeled at build time,
• Kernel permission checks controlling Binder IPC,
• Labelling of service sockets and socket files created by init,
• Labelling of device nodes created by ueventd,
• Flexible, configurable labeling of apps and app data directories,
• Userspace permission checks controlling use of the Zygote socket commands,
• Minimal port of SELinux userspace,
• SELinux support for the Android toolbox,
• Small TE policy written from scratch for Android,
• Confined domains for system services and apps,
• Use of MLS categories to isolate apps.