All the processes and knowledge were in place to make sure all considerations were taken with our software with regards to security. But... all that good work and intention goes out the window when the marketing and analysis teams could pretty much, on a whim dump any old JS onto a production page via GTM. During my 18 months there, there were numerous issues (thankfully not security issues - at least that we know of) indroduced via this method inc a full outage of the customer onboarding journey.

It is really powerful and sometimes incredibly useful in some scenarios (e.g I once built a schema.org metadata system that scraped the pages on the fly for a site with a broken CMS). Simo Ahava does clever things with it.

But from what I can tell, it seems to be a way of avoiding communication between teams, or a political power grab inside bigger companies - a parallel CMS. And the silly bit is that it's normally not doing much more than could be achieved by copy and pasting a few lines of code into a template.

Of course it all loads only when the user does not have any adblocking or tracking protections enabled.

The important point is that it's a backdoor for marketing (and adtech) teams to get around developer/security requirements. At some point, someone on those teams gets frustrated that their one-line code requests (just load this script! add a gif banner here!) keep falling behind in the backlog. That happens in part because the product team often doesn't care about marketing, and sometimes because developers know that "just one more script!" paves the road to hell. At some point the third-party that's trying to get their business going through your business convinces the marketing team to add GTM, the marketing team says to the dev team "Hey we need GTM to implement THIS script". This time, because the other side has promised them $$$ in terms ROI, the marketing team pushes really hard for it, and eventually a product manager approves the request to get them off their back. The rest, as they say, is history (at retro time, multiple times down the road).

You can tell by the URL path (it's under /content/dam) that it's served by Adobe Experience Manager (Adobe's CMS, dam stands for digital asset manager, where you store static assets like images and js). The script itself is "target.js", which is Adobe Target - their A/B framework - which "supports custom code insertion"[1] similar to a tag manager.

It's not GTM, but this is like loading the GTM script itself from archive.org.

[1]: https://docs.adobe.com/content/help/en/target/using/introduc...

That's what's great about content security policies: put a CSP on the page, and when people try to add scripts without going through proper processes it just won't run.

Unfortunately, we still have lots of 3rd party stuff in GTM, and technically any ad can run random js on our sites. Thats where most problems come from these days.

Editors still technically have the power to brick a given site through our old inhouse CMS which has no proper access control levels, hopefully not for long...

If you configure your ad network to run all ads cross-domain, then they are very limited. For example, in GPT (which I work on) you call "googletag.pubads().setForceSafeFrame(true)".

(Disclosure: speaking only for myself)

Fun story: I had a Barclaycard once. I chose to get bills/invoices via snail mail because I'm old fashioned. Didn't use the card for almost a year after signing up and then finally bought something online with it. Got an invoice next month and paid it. Then got another invoice the next month over 60ct for the invoice sent via snail mail. Fair enough, they stated that when I signed up. But then I got another bulk the following month because, you guessed it, the invoice for the invoice was sent via mail. I tried to be clever then and paid 1.20€, but that doesn't work since I still got a letter saying there's still enough money in my account covering the invoice. So after four or five months I just gave up and canceled my account.

The fact that the CSP is whitelisting archive.org makes this look like an attack to me, or at least a test run before a real attack. I don't believe this was a simple mistake.

Looks like their main homepage doesn't have a CSP policy at all https://cspvalidator.org/#url=https://www.barclays.com

I really hope they have a postmortem and actually implement a CSP for their site, pretty crazy not to, especially for a bank.

I just checked some of the local banks. Oh dear...

Hardly anybody really understands web security.

This is not about content. Content is "make a new page with that template and add a photo and the new text about XYZ product". Not a new functionality/code.

I wonder who signed this off prior to.release and what does their wiki/Jira mentions.

Edit: e-banking and other banks websites/online presence(s).

Edit2/rant: I have been the go-to audit/sec/compliance guy for more than a decade. It amazes me in this forum that there are very few discussions/POVs on the audit/security element. In most cases (like this one), an experienced auditor would have picked this up in 20mins. If only Barclays (in this case) bothered to escape the fixed-10 years old checklist/audit program these would never have happened.

It is partially baffling at least. We had to do a standalone website ad campaign for a bank (same level/recognition as barclays) once, some kind of rewards program where all you could do was browse what was possible to redeem your points for. No accounts, no cart, no integration whatsoever, it was basically a static site (with some user interactivity). We'd get scanned constantly and were always made aware of mistakes or issues, one of them being 3rd party resources.

On the other hand, I wasn't too impressed with their security scanning. Two issues had come up that made me dubious of what all good this actually did.

First was some kind of ssh vulnerability. We were using an older (but still supported) amazon linux ami. The ssh was actually patched but the version did not match what they wanted in the security tool's version. We had to get them to talk with AWS to ensure it was an actual patched version of ssh and the security scanning tool just wasnt accepting it as valid.

The other was some kind of javascript vulnerability in a library. There was an open cve on the library, an open issue on github, with comments on how to fix it, but the library itself wasn't being updated. I manually patched it and named it version x.y.z-patched or something. Report comes back that its still a vulnerability. I'm like what? Impossible I just patched it and tested it myself. The CVE no longer works. So I just renamed it to x-patched.y.z and poof, we pass validation.

This was my version time with vulnerability testing and I was kinda let down by it. I assumed they had people (or tools) actually trying to exploit the site like how I tested the patch for the javascript library prevented the CVE from working instead of just looking for version numbers and comparing to a list of known issues.

If you hadn't scanned, would you have fixed the CVE at all?

Scanning is useful to automate a "thing" but your audit is multifaceted and should probably require peer review (pull/merge requests).

In simple terms, scanning should _hopefully_ help a dev who wants to do the right thing, but it won't help a malicious dev, so you're gonna need something else.

Peer review, least privileged access, protective monitoring, etc.

I never applied as I like pushing the boundaries when it comes to using CMSs, but if they're calling it out from Day One it's also on the operator to not do it even if they could.

The Web is broken, and CORS/CSP headers will only be able to fix only some individual cases, of a bigger, currently unfixable design problem.

The tons of random JS APIs brought into the browser without a any real critical review are making the initial design of scripts on the web being inherently secure, to them not being so.

The state of things needs to be brought back to the point where arbitrary JS simply cannot mess up your browser by design, and when you can load resources from everywhere safely regardless of tricky settings of now 10+ CSP related headers.

Or alternatively, there needs to be a solution to completely shut down those APIs, any "advanced" functionality to load 3rd party resources, reinforced by cryptohashes, and signature checks to verify loaded resources.

You would still have an issue where there is simply no functionality to killswitch all those novel APIs of arguable safety, and tell the browser to shut down any script not explicitly listed as allowed on the site.

Isn't that what CSP headers are for?

I saw websites with a screen long CSP header to work around standard's inconsistencies like frame-src/child-src, and form redirects. I think it's only a matter of time when somebody will find a chink in that weak armour.

The lack of sane by-default policy makes you vulnerable the moment attacker finds a way to redirect a browser to a non-CSP protected page on your domain. Mitigations exist, but... many buts.

Reflection attacks, when attacker injects your own hashed scripts, and data exfiltrating css on pages where they shouldn't be are still possible in various scenarios unless you inline all scripts, and set CSP per every URL.

Other data exfiltration sources, and injection sinks keep being found few times a year.

CSP is a paint over rust.

What do you imagine your more restricted JavaScript being permitted to do, where it is safe to run on a banking website?

It's not the TSB IT fiasco but it's still an error on their part.

Additionally, the aggregate bandwidth cost of delivering that JS file during its lifetime is probably less than $0.05. How many copies of this file would need to be concatenated to equal the size of David After Dentist?

No one levels up on the Internet — and especially Twitter — by being calm and reasonable.

This is entirely a strawman you are burning down to make light of the fact that far from a stupid mistake, this is recklessness enabled by the joke of an "web development" industry. This stupidity is common practice and certainly no one in this thread seems even slightly inclined to clean it up.

It means they don't have their security in order, they're a bunch of amateurs and their banking license should be revoked.

It's unlikely that a content editor would be able to do this, given the industry.