4 ms·
> it is very hard to craft a set of permissions to allow that package to retry requests to certain addresses you'd like to retry without also letting it throw r
by ryukafalz 5y ago
> it is very hard to craft a set of permissions to allow that package to retry requests to certain addresses you'd like to retry without also letting it throw random system metrics it's collecting to an ad-server
If you're expecting to have to craft ACLs program-wide for that package, then sure, that's going to be hard. That's more coarse-grained than what I'm talking about here though.
Imagine, if you will, a programming environment where modules you load don't have any authority to access the network, filesystem, etc unless you pass them in. They're just not in scope. In such a language, the default way to grant HTTP access might look like this in pseudo-Python:
http = require("http")
myMaliciousLibrary = require("myMaliciousLibrary", http=http)
Now, this library has the problem you mentioned; it can make arbitrary outgoing HTTP requests, meaning it can send any metrics it collects to an ad server. It can't access the filesystem because the filesystem isn't in scope either, so what it can collect is limited, but still more access than it needs. So here's one way you might fix that (obviously highly simplified/incomplete in its implementation):
class ProxyHTTP(origin="https://example.com", http):
def __init__(origin="https://example.com"):
self.allowed_origin = origin
def get(origin, path="/"):
return http.get(self.allowed_origin, path)
http = require("http")
myMaliciousLibrary = require("myMaliciousLibrary", http=ProxyHTTP(origin="https://good-site.example.com", http))
Now, this version of myMaliciousLibrary gets an object that looks like the http library it would normally use; it just happens to ignore the origin parameter that the library passes to it and uses the one it was initialized with instead. Now, that library can make requests to good-site.example.com, but if it tries to make a request to adserver.evil.com, it'll go to good-site.example.com instead. (You might also imagine a version of ProxyHTTP that just throws an error if the request's origin isn't the same one it was initialized with, or isn't in a list it was initialized with.)
Most of today's programming languages aren't strict enough to enable this of course; JavaScript isn't there yet for example, and most other languages aren't even close to being able to do this. But that's mostly because they don't provide strict enough encapsulation, not because they're lacking some complex security enforcement mechanism.
> I think it's just because most of us accept the risk, it's highly unlikely that malicious supply chain attacks will suddenly sink our businesses so we accept a reasonable level of security in exchange for what feels like a modest risk
I just think people are accepting way more risk than they realize, given the number of dependencies in modern applications and the amount of access each of those dependencies have. It feels crazy that any one of those dependencies in any application could exfiltrate massive amounts of sensitive data from any machine it happens to run on.
- munk-a 5y agoI think there'd be a lot of reliance on all these fundamental components working correctly (and prohibiting other components i.e. "We're using this curl library at a basic level and exposing a safe interface through this protected library but somehow blocking calls from code outside the library") which might have serious repercussions for code reuse. There are ways you can instruct an OS to block calls to certain library functions/memory ranges (i.e. remove and grant elevations privileges) but I think such a system would need to be designed from the ground up. If you can still `require(lib/reallyOldCurl)` then your protections might allow linters to be able to mark packages as unsafe, but I think it'd be extremely difficult to block access without an extremely fundamental design intent. I appreciate your reply quite a bit though as I was envisioning the restrictions being defined on a universal package level (aka lpad is given no disk access) rather than being delegated to the consuming developer.