Microsoft and Indiana University find “pileup” flaws could allow for nasty apps on Android phones following an OS update
Weaknesses in the app update process on Google’s Android operating system could allow attackers to sneak malicious applications onto user devices.
The “pileup” (privilege escalation through updating) vulnerabilities would let an ostensibly nonthreatening app, with limited permissions, turn into a piece of data-stealing software after an update to the OS, according to researchers from Microsoft and Indiana University.
Android update danger
They uncovered six Pileup ﬂaws within Android Package Manager Service, looking into 3,522 Android source code versions customised by Samsung, LG and HTC.
The researchers said exploits would have potentially dire consequences for users. Using a shared user ID (UID) across apps, they were able to show how a malicious app could substitute for system apps such as Google Calendar. This “package name trick” was found to work on the Android browser, allowing them to toy with cookies, cache, security conﬁgurations and bookmarks.
A malicious app could also get permission to access voicemails, user credentials, call logs, notiﬁcations of other apps and text messages.
Exploits could also be used to prevent the user from installing system critical apps, like Play Services, which is used to update Google apps and apps from the company’s store.
“The malware can also gain complete control of new signature and system permissions, lowering their protection levels to “normal” and arbitrarily changing their descriptions that the user needs to read when deciding on whether to grant them to an app,” the paper read.
“Particularly, we found that customised OSes are highly susceptible to the Pileup attacks, due to a large number of system capabilities they bring in for each upgrade.”
They said they had informed Google and the relevant manufacturers of their findings and were working on patches.
The researchers created software called SecUP, which deploys a scanner on the user’s device to detect apps that would get malicious upgrades. The app can now be found on Google Play.
Google had not responded to a request for comment at the time of publication.
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