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Android Security

One Billion Android Devices Open To Privilege Escalation 117

Posted by timothy
from the that's-beeeeeellion dept.
msm1267 (2804139) writes "The first deep look into the security of the Android patch installation process, specifically its Package Management Service (PMS), has revealed a weakness that puts potentially every Android device at risk for privilege escalation attacks. Researchers from Indiana University and Microsoft published a paper that describes a new set of Android vulnerabilities they call Pileup flaws, and also introduces a new scanner called SecUP that detects malicious apps already on a device lying in wait for elevated privileges. The vulnerability occurs in the way PMS handles updates to the myriad flavors of Android in circulation today. The researchers say PMS improperly vets apps on lower versions of Android that request OS or app privileges that may not exist on the older Android version, but are granted automatically once the system is updated.

The researchers said they found a half-dozen different Pileup flaws within Android's Package Management Service, and confirmed those vulnerabilities are present in all Android Open Source Project versions and more than 3,500 customized versions of Android developed by handset makers and carriers; more than one billion Android devices are likely impacted, they said."
Handily enough, the original paper is not paywalled.
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One Billion Android Devices Open To Privilege Escalation

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  • Nope (Score:5, Informative)

    by AmiMoJo (196126) * <{ten.3dlrow} {ta} {ojom}> on Saturday March 22, 2014 @06:57PM (#46554559) Homepage

    What the summary fails to explain properly is that this vulnerability only works with permissions that are new when the device gets an OS update. Say you install an app and it asks for permission to use NFC, but your device's OS is old and doesn't support NFC (pre 4.0 I think). You install it anyway. Then you upgrade the OS and now it supports NFC. The app then gets the NFC permission without any further prompts or warning to the user.

    That is certainly an issue, but not the huge gaping security flaw the summary makes it sound like. Apps can only ask for normal permissions that the OS offers, not bypass security or the sandbox. It's basically a UI issue.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Is that even a problem? When you download an app from the Play Store, it gives you a list of permissions that the app requests. You give it permission when you download the app. If Play does not list an app if your version of Android or phone does not support the feature, then that's potentially a problem, but an easy one to fix.

      • Is that even a problem? When you download an app from the Play Store, it gives you a list of permissions that the app requests. You give it permission when you download the app. If Play does not list an app if your version of Android or phone does not support the feature, then that's potentially a problem, but an easy one to fix.

        Sounbds like "grandfathering". If the permission was available in the older Android by virtue of not having an explicit block, it continues to be available on the newer version even though blocking is now available.

        Proper security paranoia says that the opposite should occur. That if a service is now blockable, it should block until the user explicitly agrees otherwise.

        On the other hand, recent updates on my tablet have listed privileges that they were newly requesting as part of the update approval process

    • Re:Nope (Score:5, Insightful)

      by Rick Zeman (15628) on Saturday March 22, 2014 @07:13PM (#46554637)

      What the summary fails to explain properly is that this vulnerability only works with permissions that are new when the device gets an OS update. Say you install an app and it asks for permission to use NFC, but your device's OS is old and doesn't support NFC (pre 4.0 I think). You install it anyway. Then you upgrade the OS and now it supports NFC. The app then gets the NFC permission without any further prompts or warning to the user.

      That is certainly an issue, but not the huge gaping security flaw the summary makes it sound like. Apps can only ask for normal permissions that the OS offers, not bypass security or the sandbox. It's basically a UI issue.

      Yeah, and since the carriers update Android devices so infrequently the threat exposure is more theoretical than practical.

      • by AmiMoJo (196126) *

        PROTIP: Never buy a carrier branded phone. It should be obvious to everyone by now, but apparently not.

      • by phorm (591458)

        Then you upgrade the OS and now it supports NFC. the carriers update Android devices so infrequently the threat exposure is more theoretical than practical.

        Indeed. Beyond that, many such upgrades are inherently hardware-based, rather than software. Even if you upgrade your old Galaxy 2 to an OS version that has NFC, the hardware lacks the capability and thus the permissions mean nothing.

      • by Rob Y. (110975)

        I wonder, though. When you buy a new Android phone and sign in to Play, it downloads (or at least offers to) all the apps you had on your old phone. Does the same thing happen there - i.e. if you had apps with privileges that weren't available on your old phone, do they get automatically installed on the new phone with all the privileges - or is it treated like an update with new privileges, where you need to agree to the installation before it will install? If so, I imagine that could be changed in the P

        • Re:Nope (Score:5, Informative)

          by alostpacket (1972110) on Sunday March 23, 2014 @12:43PM (#46557929) Homepage

          I wonder, though. When you buy a new Android phone and sign in to Play, it downloads (or at least offers to) all the apps you had on your old phone. Does the same thing happen there

          No, this particular exploit requires the malicious app be on a phone prior to an OS update. Additionally these apps would never* make it on the Play store as they have detectable characteristics (such as trying to use the same "Shared UID" of another app). In order to upload an app with the same Shared UID, you would need the same keystore to sign your app. Basically the way this bug works is exploiting the reverse of how the package manager grants precedence. The package manager give precedence to what is on the device first. So anything "updated" from the Play store, even if they spoofed the Shared UID and signature, would fail to install. The bug is that an app can "steal" the ability to control the permission completely, AND install itself or block the install of the legit version of an app.

          So TL;DR: This definitely is a rather nasty privilege escalation bug in the package manager (if the paper is correct and I am reading it correctly), but one would likely need to side-load (or use a different app store) the malicious app prior to an OS update to get caught by it.

          Agreed about permissions in general though. Personally I try not to give out contacts to any app unless they happen to be a type of "contact manager/replacement". Most apps can request a user use the default "contact picker" to add a contact, or share, or the like. No permission is required for this. The only reason apps request this is to prefill those "share with a friend" fields and to spam. This is similar to READ_PHONE_STATE, there are few legit reasons for an app to need this anymore. Apps can launch the dialer and prefill the number sans the permission, just not complete the call. They also have other ways to generate a UUID for the device without the IMEI, or the other info provided by READ_PHONE_STATE.

          The USB storage permissions are antiquated, but not as sensitive. Apps do have private storage but this used to be quite limited in the earlier days of Android. The Nexus S was one of the first to come with a single, large internal storage (although even that was still partitioned). Prior to that you had a limited protected storage and an SD card. Nowadays they are adding better "Read" file permissions.

          Finally, I think much of this stuff could be requested at time-of-use, rather than install. But they have to balance the "Are you sure you want to allow X?" disaster that was Windows UAC vs. sensible permissions. It is not as easy as it looks.

          * (Well maybe not never, but very close to never...)

    • That is certainly an issue, but not the huge gaping security flaw the summary makes it sound like

      A security flaw is a security flaw. Whether or not it's a "gaping hole" it still can be exploited.

      For that, I sincerely thank Microsoft for so kindly pointed out that security flaw.

      No matter what's the ultimate intention / agenda of Microsoft in this case, with this security flaw exposed, let us hope that Google can do something to plug it, and make those "Billion Android Devices" just a little bit more safer.

      • by Jane Q. Public (1010737) on Saturday March 22, 2014 @08:15PM (#46554915)

        "For that, I sincerely thank Microsoft for so kindly pointed out that security flaw."

        "Kindly"? Are you serious? There was nothing "kind" about it. It's anti-Android PR for Microsoft. Why the hell do you think Microsoft was involved with looking into it in the first place? The goodness of their hearts? Puh-leeeeeze.

        • Certainly kinder than discreetly e-mailing their findings to every shady source of malware they know of. With so many years of experience, I'm sure they have a list.

          • by symbolset (646467) * on Saturday March 22, 2014 @09:30PM (#46555175) Journal
            The source of malware still has to get you to install their app and then update your Android. And it's only a problem if you didn't already assume that when you gave the app that permission it would gain it when available. The risk is way overstated. If this is the mud Microsoft can sling, I find that comforting.

            Now let's talk about that last patch batch where IE couldn't even safely display a JPEG in any currently supported version on any version of Windows.

          • by Anonymous Coward

            Certainly kinder than discreetly e-mailing their findings to every shady source of malware they know of. With so many years of experience, I'm sure they have a list.

            Er yes, but this is the company that insists everyone else does responsible disclosure and has threatened security researchers who don't. I sure hope the next people to find a major, wormable Microsoft vulnerability remember about this generosity.

          • That would be true if the security flaw could be exploited. But apparently, it would appear that this flaw is mostly theoretical. This article is MS funded anti-Android FUD.

        • by Anonymous Coward
          Probably the same reason google does the same thing, to analyse how their competitors are doing. This method of exposure of vulnerabilities is what google want (as was demonstrated by them using the same method when they found vulnerabilities in MS products). They should be kindly thanked as they are following the procedure that Google want people to follow, their motivation is irrelevant,.
        • by Chokolad (35911) on Saturday March 22, 2014 @10:01PM (#46555323)

          "Kindly"? Are you serious? There was nothing "kind" about it. It's anti-Android PR for Microsoft. Why the hell do you think Microsoft was involved with looking into it in the first place? The goodness of their hearts? Puh-leeeeeze.

          What do you think of IE vulnerabilities found by Googlers ?

          http://www.google.com/about/ap... [google.com]

          • "What do you think of IE vulnerabilities found by Googlers ?"

            I wasn't saying Microsoft is any worse. Just that they weren't doing it for the sake of charity.

            • by Anonymous Coward

              Don't let these bullshitters get to you. Notice that all the Google flaws are accompanied by CVE numbers and a Microsoft, or other vendor, bulletin. This is for two reasons; firstly these are real flaws (Microsoft is including applications which openly say they use a particular feature but only get it added during an upgrade - in other words things which can't possibly be seen as security vulnerabilities) and secondly Google first took them to Microsoft before releasing them.

              What Microsoft has done by pu

        • by gerardrj (207690) on Saturday March 22, 2014 @10:14PM (#46555391) Journal

          Considering the amount of money that Microsoft makes in patent licensing fees from Android I don't know how they could have any financial reason to want Android to go away. At the moment I suspect that Microsoft makes more money from Android than it does Windows Phone.

          • by Jane Q. Public (1010737) on Saturday March 22, 2014 @10:35PM (#46555485)

            "Considering the amount of money that Microsoft makes in patent licensing fees from Android I don't know how they could have any financial reason to want Android to go away. At the moment I suspect that Microsoft makes more money from Android than it does Windows Phone."

            That last bit is exactly why they want Android to go away. They don't make nearly as much money on Android as they'd make if all those same phones were Windows. Every Windows phone they can sell in place of an Android phone is more money in their pockets.

            Sure, they'll make money off of Android where they can. But they'd rather it simply wasn't there.

        • "For that, I sincerely thank Microsoft for so kindly pointed out that security flaw."

          "Kindly"? Are you serious? There was nothing "kind" about it. It's anti-Android PR for Microsoft. Why the hell do you think Microsoft was involved with looking into it in the first place? The goodness of their hearts? Puh-leeeeeze.

          That was a big one. You're lucky the mods nearly got it full force too. Next time you hear someone yell "duck" don't stand there looking for one just hit the deck or the Woosh may be fatal.

        • by Sun (104778)

          As long as the research is valid and the conclusions correctly presented (which, in this case, they do not seem to have been), I don't care for the motive.

          Shachar

          • by swillden (191260)

            As long as the research is valid and the conclusions correctly presented (which, in this case, they do not seem to have been), I don't care for the motive.

            No argument. The research seems decent and worthwhile. The tone of the press release is what's eye-rollingly ridiculous. This is a minor security UI deficiency, but they're selling it as a "privilege escalation", which is normally understood to mean the ability to break out of the sandbox at least, and usually implies root access.

        • by the_B0fh (208483)

          So... what's your stance on all those vulnerabilities published by Google on Microsoft's applications?

          [and jesus, I can't believe I'm "defending" Microsoft]

      • am I going to open an xterm and type call_accept on a nice debian system.
    • Oh please.

      Anyone can write an escalation ad on a mobile website and make it pretend it is an os update and have it installed that way.

      If this were Windows Phone everyone would be screaming INSECURE.

      • What are you talking about? A fake OS update? Does that have anything at all to do anything? A fake update wouldn't add any new system capabilities, so apps wouldn't gain any new capabilities.

        Did you read the comment you replied to? Or TFA, or anything to get a clue what that topic is?

    • Re:Nope (Score:5, Insightful)

      by Todd Knarr (15451) on Saturday March 22, 2014 @11:03PM (#46555583) Homepage

      The problem here is that the permissions system goes beyond just ordinary user permissions. The system itself uses permissions to control which parts of the system can do what, and those permissions are normally only available to system components (trying to install an app that asks for those permissions results in the app being rejected because it doesn't qualify to get those permissions). For instance, the "Across_users" permission was added to Android 4.2, and allows system components to break through the normal restrictions that separate different users in the system. An app with this permission can reach out and directly affect everything on the phone, not just the things that belong to it. It's restricted to Android system components only. But if I install an app that asks for it on an Android 4.0 device, the app will install without any warnings. If the device is then upgraded to 4.2, the app will silently get the "Across_users" permission activated. So now we have a user-installed app which has a permission that it could never legitimately have that lets it bypass security and the sandbox, and the user will be unaware of the problem. It's very definitely NOT just a UI issue.

      In the Unix world it'd be equivalent to finding an other-writable directory sitting in the root user's PATH, and in that directory are executables named "ls", "cat" and so on. It's the kind of thing that'd make a security admin excrete cinder blocks at velocities sufficient to have them achieving high orbit, ceilings nonwithstanding.

      • Re:Nope (Score:4, Insightful)

        by Bert64 (520050) <(bert) (at) (slashdot.firenzee.com)> on Sunday March 23, 2014 @03:17AM (#46556229) Homepage

        On the other hand, the likelihood of this vulnerability actually being exploited is quite low for quite a few reasons... Primarily, because it requires that you first install a malicious app and then upgrade to a version of android which actually implements some new permissions...

        1, very few users ever update (or even have updates available)
        2, manufacturers will sometimes patch android but usually not provide updates to whole new versions and the small incremental patches wont introduce any new permissions
        3, now that this issue has been discovered its highly likely that future updates will contain a fix for it, and users are unlikely to update to a version that isnt the latest available for their particular handset, so *if* they can and do update they will be patching this issue anyway.

        • by AmiMoJo (196126) *

          Also, you would have to side-load any such app because Google won't allow apps that request system permissions on to Play.

        • by phorm (591458)

          Or to just commandeer the next "flappy bird" or whatever from the author. Of course, for stuff like that most people would ignore new permissions even if the phone displayed them in a floating red hologram hovering right in front of the users' eyes.

      • Did you actually test this ?

      • Re: (Score:1, Interesting)

        by macs4all (973270)

        But if I install an app that asks for it on an Android 4.0 device, the app will install without any warnings. If the device is then upgraded to 4.2, the app will silently get the "Across_users" permission activated. So now we have a user-installed app which has a permission that it could never legitimately have that lets it bypass security and the sandbox, and the user will be unaware of the problem.

        Mod Parent UP.

        That is EXACTLY it in a nutshell. Perfectly described.

        Pretty devious way for someone like the NSA (or a Prince from Nairobi) to get their hooks into your Android.

        Shudder...

    • by rabtech (223758)

      That is certainly an issue, but not the huge gaping security flaw the summary makes it sound like. Apps can only ask for normal permissions that the OS offers, not bypass security or the sandbox. It's basically a UI issue.

      Correct. The huge, gaping security flaw with Android is the same one that afflicted ActiveX in Internet Explorer: Assuming that the majority of users
      a) have a clue what any of the permissions actually mean
      b) can trust the app not to abuse the permissions it has (or contain flaws that allow it to be hijacked)

      The reality is that 100% (rounding up from normal people to geeks) of people simply tap accept, click OK, etc and move on with their lives. Those annoying dialogs are just how you use phones/computers. T

  • by MrKaos (858439) on Saturday March 22, 2014 @06:59PM (#46554583) Journal

    Handily enough, the original paper is not paywalled.

    Wow, a freeby from Microsoft, how incredibly generous. Google will probably thank them for pointing it out. Isn't it nice how everybody just, *gets along*.

  • HMmm (Score:2, Insightful)

    by Stumbles (602007)
    I expected better from Google.
  • This depends on upgrades. Carriers, upgrade?

    Hell, my wife and I are on different versions of Android, same carrier, same phone, both say they're fully up to date.

  • by mveloso (325617) on Saturday March 22, 2014 @08:12PM (#46554899)

    Luckily for most Android users Android is almost never updated, so in real life there's no real vulnerability.

  • You'll find the scanner titled "Secure Update Scanner" in the Play store.

  • Old version of Android may be susceptible to hijacking by a malicious app. Such a malicious app can only get onto the device by direct user action ..
  • Wow (Score:5, Interesting)

    by slapout (93640) on Saturday March 22, 2014 @08:48PM (#46555055)

    There are one billion Android devices? That's awesome!

  • Think of all the help Microsoft could get spotting security flaws if Google and Stanford could look through the Windows source whenever they chose.

  • I'm pretty sure this story calls for a little Bible verse, from the book of Matthew.

    "Thou hypocrite, cast out first the beam out of thine own eye; and then shalt thou see clearly to cast out the mote out of thy brother's eye."

    Now brothers and sisters, please join me in a song from page 126 of your hymnal, "Open My Eyes That I Might See".

    • This is oddly appropriate.
      • by PopeRatzo (965947)

        "Oddly"? It's exactly appropriate to Microsoft pointing out exploits in Android.

        It's the pot saying the shovel is insecure by design.

        What, you thought that just because it's a biblical quotation that it's gotta be some religious maniac making an off-topic post?

  • And I still don't give a crap.
  • by Ukab the Great (87152) on Saturday March 22, 2014 @10:11PM (#46555381)

    That there are 3,500 customized versions of Android developed by handset makers and carriers is really a news story unto itself.

    • by AmiMoJo (196126) *

      Counting the way they do you could say that there are 10,000+ versions of Windows out there. Every random OEM that loads up some crapware or changes the wallpaper counts as a new custom version to them. Of course in reality it makes little difference to developers or users (updates are provided by Google, the same way as "custom" versions of Windows still get updates from Microsoft).

  • Privilege escalation? That phrase, I don't think it means what you think it means.

  • by Srin Tuar (147269) <zeroday26@yahoo.com> on Sunday March 23, 2014 @12:46AM (#46555843)

    In that it still doesnt allow line-item veto of app priveleges.

    This should be the most basic feature.

  • So sweet of Verizon to not provide updates on a timely basis, then, which prevents this kind of attack from ever causing problems.
    So I turn to CyanogenMod or similar, which I'm sure will have patched this by the time there's another upgrade.

The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" (I found it!) but "That's funny ..." -- Isaac Asimov

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