BMW ConnectedDrive Session Validation

A session validation approval web vulnerability has been discovered in the official BMW ConnectedDrive online service web application. The vulnerability allows remote attackers to manipulate specific configured parameters to compromise the affected web application service.

PaX Reference Count Overflow Mitigation Bypass

PaX contains a mitigation for reference count overflows that is intended to prevent atomic_t variables from reaching 0x80000000 and, more importantly, wrapping around to zero. A documented special case on x86 is that, because “atomically increment unless current value is X” cannot be implemented without a cmpxchg loop, the code instead increments the counter, checks for an overflow and, if an overflow happened, immediately decrements the counter back.