4 ms·
The problems which were pointed out are good ones, and they should be fixed. Fortunately, they are easy to fix. In the grand scheme of things, though, this i
by tytso 15y ago
The problems which were pointed out are good ones, and they should be fixed. Fortunately, they are easy to fix.
In the grand scheme of things, though, this isn't as bad as it seems, since the vast majority of Android applications run in the Dalvik JVM. Hence the amount of code that is subject to weaknesses that could be exploited by the attacker to cause a jump into the non-randomized dynamic loader (for example) are much smaller.
Of course, there could still be bugs in native code applications, libraries, and system executables, so the ALSR should definitely be improved. Again, fortunately, this should be relatively easy to do.
- jonoberheide 15y agoThere's still a large attack surface of native code in the Android platform. I've heard WebKit has a few bugs... :-P
- ch0wn 15y agoThis is why I think Chrome for Android is a big deal. The browser will always be one of the easiest ways run an exploit. With the browser tightly coupled with the OS, many old phones will never receive an update for it. The WebView as attack target is a different story, though.
- alecco 15y agoYou made a great point. Why did you have to ruin it with an emoticon?
- sukuriant 15y agoBecause they're common speech patterns on the internet these days, where it's difficult to show emotion via text. You could have just as easily said "why did you grin after saying you ate pizza?". A better question might have been: "Why the 'sticks tongue out at in silly manner' face?"
- saurik 15y agoYes, it should be easy to fix. That said, you downplay the weakness too strongly: it was because of the lack of working ASLR that allowed me to use the mempodipper exploit (as my port, "mempodroid" [1]) to get root on all the current ICS devices. (While sometimes you can adjust an exploit to work around ASLR, this exploit requires you to know an absolute address before the program executes.) [1] https://github.com/saurik/mempodroid https://github.com/saurik/mempodroid
- jonoberheide 15y agoYeah, mempodroid is a great example. You'd need to randomize the location of the setuid executable (w/PIE), randomize of the linker, and implement something like GRKERNSEC_BRUTE to prevent trivial local bruteforcing of a usable address. Speaking of which, spender's recent blog post gives a good overview of some of the grsec/PaX mitigations that would hamper the exploitation of the /proc/pid/mem vuln: http://forums.grsecurity.net/viewtopic.php?f=7&t=2939 http://forums.grsecurity.net/viewtopic.php?f=7&t=2939
- saurik 15y agoInteresting... it never occurred to me that brute forcing an address was feasible enough to bother with. ;P (edit: Although, thinking more, some exploits have a more constrained range of addresses. That said, even here we have a 2-3GB area, but could probably expand the target to "any instruction executed between these points", which might be as much as a kilobyte; requiring just a few million attempts isn't that unreasonable.) Looking at GRKERNSEC_BRUTE, however, it would not affect this exploit: it is designed to penalize the parent for forking exploitable children (so as, for example, to keep new copies of Apache from coming into existence rapidly enough for them to be remotely exploited); however, here we are assumed to have control of the parent, so we can just add a layer of indirection, never reusing direct parents.
- jonoberheide 15y agoGRKERNSEC_BRUTE will also trigger for suid binaries (in the case of memprodroid, run-as). See gr_handle_brute_attach() for details.