> The attacker can submit a maliciously crafted database file to the application that the application will then open and query.
I think it’s not impossible to secure SQLite better but it takes some work (like how Chrome sandboxes it in a separate process).
[1] https://www.sqlite.org/security.html [2] https://www.sqlite.org/cves.html
I don't agree. That document states that the CVEs have historically required one of two preconditions:
> The attacker can submit and run arbitrary SQL statements.
> The attacker can submit a maliciously crafted database file to the application that the application will then open and query.
If you look at the actual list of CVEs, all but one start with ‘Malicious SQL statement’. The single one that doesn't is suffixed with ‘The bug never appeared in any official SQLite release’.
In other words, there has never been an official release of SQLite which was vulnerable when presented with a crafted database file.
The list on the page is partial, and the language on that page is disturbingly dismissive. Reading leaves me more concerned that they're too arrogant to take security researchers seriously.
Besides that the large majority of thinks tested in your link are irrelevant for the security in this use-case. They do matter if you need fully stable de- and re-serialization or e.g. have a fully trusted validator. E.g. for certain security token use-cases it matters. Many of the thinks which are marked as failure could even be considered as a "more robust" or "more secure" (through not fully standard conform) parser. E.g. parsing tailing commas (disallowed by JSON), rejecting certain unescaped control/special characters (which JSON allows), rejecting to long field values (which JSON allows) or similar. What matters is that a) it has a protection about to deep recursion and as such no stack overflow can happen, b) it makes sure the text it outputs is correctly encoded (independent of weather or not it was well-formed in the JSON blob) and c) it doesn't crash in a way which leads to security problems (which the test suite you linked doesn't differentiate from "acceptable" crashes).
Surely if one uses one parser to verify the payload and another to use it, a disaster comes as was with IPhone verification bug.
Link: https://www.sqlite.org/gencol.html
Example:
CREATE TABLE t1(
a INTEGER PRIMARY KEY,
b INT,
c TEXT,
d INT GENERATED ALWAYS AS (a*abs(b)) VIRTUAL,
e TEXT GENERATED ALWAYS AS (substr(c,b,b+1)) STORED
Note how you can call functions in the columns. Thats one feature which a hardened sqlite for less trusted documents would need to not have.
SQLitte is mostly used in situations where neither the database nor the SQL statements can be provided by the attacker. If SQLite is used to exchange data both of these attack vectors are available.
18 CVEs
http://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=xml
> There are 1776 CVE Records that match your search.
Do I win?
> There are 126 CVE Records that match your search.
More seriously, my point is that SQLite is very unlikely to be the most vulnerable piece of software in your stack. It's probably the most stable and bug free piece of software that you use on a day to day basis that hasn't been formally proven correct. Even openoffice itself has more CVEs: https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=openoffice
And some of them are due to the very issue I brought up above...
> CVE-2012-0037 Redland Raptor (aka libraptor) before 2.0.7, as used by OpenOffice 3.3 and 3.4 Beta, LibreOffice before 3.4.6 and 3.5.x before 3.5.1, and other products, allows user-assisted remote attackers to read arbitrary files via a crafted XML external entity (XXE) declaration and reference in an RDF document.
Sqlite is very high quality, but I am rather doubtful this is true if you actually care about having a secure system to start with. I can think of three main reasons an office suite would have serious security vulnerabilities:
1. It's written in an unsuitable, memory-unsafe, programming language (as most office suites sadly are).
2. It includes an unsuitable programming language for scripting purposes (Word Macros are of course infamous for this).
3. Vulnerabilities in one of its dependencies (like XML parsers)
If you care to, 1 and 2 are very easy to avoid and 3 will be pretty hard to avoid completely, but you can limit your exposure. You need a GUI toolkit at the minimum, but you can completely avoid parsing as an attack vector by either not using a braindamaged format like XML in the unlikely case you don't need compatibility, or if you must, use an xml (zip etc.) parser written in a memory safe language. If you followed all other steps, but chose sqlite instead, I'd say chances a very good it's now your main vulnerability.
I dunno man, I feel like my original statement is pretty reasonable. Let's please not move the goalposts to the moon. :)
Personally I find this a very unreasonable thing to accept. Secure (single user) text processing (etc.) is not a hard problem at all and there is zero reason it should create any security risks.
Crap passwords (and security practices) are not pertinent at all here, unless you also argue that Boeing shouldn't really bother to make airplanes with non-lethal autopilot interactions because being killed by a mis-designed airplane is the least of risks to the typical US citizen's life give how obese he or she is.
The pertinent question is: if you are to design a wordprocessor, should you avoid baking sqlite into the design because of security concerns? I think you should. Sqlite is written and tested very well, but it is written in not formally verified C, and using a memory unsafe language for reading potentially hostile databases poses a completely unnecessary and avoidable security risk.
A two-piece component (DB + sandbox) that you use for 100 different things is going to end up much more secure (overall) and require less human effort than maintaining 100 different systems for each use case.
It's like "don't roll your own crypto". That is the advice not because it's impossible to roll your own secure crypto, but because it is just much more likely that you will repeat bugs that other people have already figured out, so it is better if everyone is using one library so that when an issue is found and resolved, it applies to everyone. It is still good advice even though that 3rd party crypto lib is probably going to have a lot of unneeded functionality that actually increases the overall attack surface area than if you made your own for whatever your specific purpose is. I think the same logic applies here.
The change from storing the inner document format in something which is not XML is completely independent of changing the outer container to sqlite.
SQL isn't really suited as a markup language so storing styles "flowing" text in it isn't that good of an idea. The article only recommends storing all separate blobs of styled text in tables (it also sidesteps the whole problem about flow text across multiple pages by simple using slides as an example ;=) ).
Lastly I'm against using a "stock"/unhardened sqlite version, not sqlite in general. Ironically on of the features I would disable for now is related to text search but I don't remember the name of it so I can't really use it as an argument :=/.
So if you ask me:
- Change containers to a different format then zipped sql files, consider sqlite but use a hardened feature limited sqlite version.
- Change the inner representation away from XML(1)
(1): Ok, there are ways to safely use XML but this isn't useful for this discussion and they require a bunch of thinks which all reduce usability (of the XML library) and performance and only work for certain use-cases where you e.g. do not need fully stable serialization and de-serialization and might be limited to a subset of XML and don't rely on the verifier for anything "safety" realated and preferably don't use C/C++ to write a parser... so it's easier to just not do it tbh.