Spengler: False Boundaries and Arbitrary Code Execution

Brad Spengler has posted a review of Linux capabilities and how they can be leveraged for full root privileges on the grsecurity blog. In short, 20 of the 35 capabilities bits allow actions that can result in root privileges from an exploitable program. "As mentioned earlier, there are 35 capabilities currently implemented. I'll now discuss each capability that is effectively equal to root and a rough description of how each transition is made. I will try to make a distinction between cases that are generally applicable and those that are situational. Since we've already established that real uid 0 is equivalent to having full capabilities on any normal system, I'll assume we're a non-root user with only the mentioned capability raised." (Thanks to Dan Carpenter.)

Comments (45 posted)