Tuesday, February 14, 2012

iOS .sinf Name Calling

In my ever present quest to identify the true owners of stolen iPods, I made discovery in iOS while examining a Touch that may be probative: the app .sinf files found in the /private/var2/Applications sub folders.  According to File-Extensions.org:
The SINF file extension is associated with applications for Apple iOS operating system that is used in Apple iPhone, iPad and iPod Touch. File contains information about digital rights that are applied in application. The SINF file is stored in an IPA iOS application archive.
I found that by searching the ../Applications directory for .sinf files, and then grepping for the term "name", the Apple Store real name associated with the app can be discovered.  On the Linux command line, this can be accomplished very quickly with:
$ find private/var2/Applications -name "*.sinf" -exec strings -f {} \; | grep name
Modification dates for the files can be used to create a timeline of activity for the device and perhaps demonstrate when new residents moved in, so to speak.  The find command can by used with stat to quickly provide a list of date stamps:
$ find private/var2/Applications -name "*.sinf" -exec stat {} \;
But, even better, you can put it all together in a fairly simple command and create csv output for examination and sorting:
$ find private/ -name "*.sinf" | while read i; do name=$(strings "$i" | grep name); date=$(stat -c %y "$i"); echo -e "$i,$name,$date"; done

It appears from content that I have uncovered in a suspected stolen device, that the real name of the Apple Store account used to install the app is embedded in the .sinf file at the time of installation.  If this is the case, a stolen device, though it have the device name changed and the true owner's data deleted, may still have applications that were installed with the owners Apple Store account! 
Testing still needs to be done for verification, and I don't currently have any test devices to properly test.  If you are able to conduct any validation studies, please comment on this post with your findings.  I'll amend this post once I'm able to conduct my own studies or receive reliable findings from others.