Fast16: High-precision software sabotage 5 years before Stuxnet
sentinelone.com
sentinelone.com
That kind of notation, called SCCS/RCS, is the equivalent of finding a rotary phone in a modern office. Nobody uses it in 2005 Windows kernel code unless their programming background goes back decades, to government and military computing environments
—
The astrophysics lab I worked at in 2006 was still using svn and had a bunch of Fortran with references to systems from the 70s and 80s. The code ran perfectly well thanks to modern optimizing compilers and having moved from Vax to Linux in the 90s, it was a surprisingly seamless transition.
It reminds me of a conference talk I’ve referenced before “do over or make due” basically implying rewriting large amounts of mostly functioning code was not worth the effort if it could be taped together with modern tools.
What’s interesting about the malware in this post is that it goes one step further: instead of exploiting mismatches, it corrupts the computation itself — so every infected system agrees on the same wrong answer!
More broadly: any interpretive mismatch between components creates a failure surface. Sometimes it shows up as a bug, sometimes as an exploit primitive, sometimes as a testing blind spot. You see it everywhere — this paper, IDS vs OS, proxies vs backends, test vs prod, and now LLMs vs “guardrails.”
Fun HN moment for me: as I was about to post this, I noticed a reply from @tptacek himself. His 1998 paper with Newsham (IDS vs OS mismatches) was my first exposure to this idea — and in hindsight it nudged me toward infosec, the Atlanta scene, spam filtering (PG's bayesian stuff) and eventually YC.
https://users.ece.cmu.edu/~adrian/731-sp04/readings/Ptacek-N...
The paper starts with this Einstein quote "Not everything that is counted counts and not everything that counts can be counted", which seems quite apt for the malware analyzed here :)
Where do you think the LLM is getting it from? ^_^
it was generated that way, or else this person happens to know the correct combination of buttons to make that happen.
in 2026, at least 20-40% of social media traffic is bots (and probably higher with better LLMs), so it is usually safer to just assume.
Thanks for sticking up for my humanity ;)
Yes, some people care about maximum impact of their words.
> at least 20-40% of social media traffic is bots (and probably higher with better LLMs), so it is usually safer to just assume.
Look around you. If you see 40% bots in HN comments, find a therapist.
I still use RCS today. It's certainly not my preferred option, but my collaborator likes it, and it's not too annoying for me to use.
Do you mean skeptical on which government was responsible or that it was in fact a government effort?
I can see how attribution could be debatable (between two main suspects mainly), but are / were there any good arguments against this being a gov effort? I would find it highly unlikely that someone other than a gov could muster up so much domain knowledge, source pristine 0days and be so stealthy at the same time.
Perhaps you meant cvs? Subversion was released in 2004 and git appeared in 2005.
The reference to the 70s and 80s code didn’t imply it was version controlled before svn/cvs though if that’s what you meant, but by that time it was and still had old timestamps commented in the text files.
gcc, for example, transitioned to subversion in 2006 and switched to git only in 2019 [0]
Every academic institution, every school, all under the radar of recruitment and more. It's difficult to believe, but the network is real.
There are certainly people here on HN who've been solicited, most who'll never mention it.
It's fun to imagine, though, what tight groups of highly motivated, stupidly intelligent people can do when they collectively commit to doing so - and with a hefty budget to assist.
But then I am getting too utopian
But we are, precisely where we are
Edit: I thought it prudent to leave a reminder, that the US military operates beyond patent regulations. If they want or need something, the silly games end there. And they do what they will.
Rather this was developed by a team of 6-8 people. Maybe two or three of them working on the implant, another engineer handling the exploits and propagation, and yet another building the LP and communications channels. They are supported by a scientist with deep knowledge of the process they are messing around with (say developing nuclear weapons), and a mathematician that knows how to introduce subtle and undetectable errors.
1. CIA had recruiting events that invited STEM majors at my university, I suspect they do this very broadly.
2. Our funding came partially from the Air Force and part of the rules was our data and source had to be open. We know from conversations and other details from integrating with Air Force partners that they had models like ours that were an order of magnitude more accurate because they amalgamated models from all academics in our field and had their own career scientists on staff (often coming up through military ranks)
A lot of the C code you see for numerics is a straight up f2c run checked in.
That meant the files has the entire "$Revision: 1.3 $" nonsense and "file changelog" at the top too - though many newer files never bothered to include the tags to actually get RCS to replace them. Inconsistent as hell.
And while the "family" of devices the software was for traces it's origin to the mid '90s, functionally none of the code was older than ~5 years at that time.
Naturally even with only a few tens of engineers it regularly messed up, commits stepped on each other's toes and the entire tree got corrupted regularly. For fun I wrote a script that read it all and imported the entire history into git - you only had to go back a few years before the entire thing was absolute nonsense.
I have no idea why that was still being used then, but I assume it had been in use from the very start of that entire hardware family. Perhaps as it was fundamentally a "hardware" company - which until surprisingly recently seemed to consider "source control" to be "shared folders on remote machines" - "software" source control wasn't considered a priority.
And I couldn't find any tool that supported the mks "project" files that linked multiple rcs revisions into a single "commit", so something a little custom was needed anyway. At least for the ancient mks version used.
Quite a bit of effort was put into it during the "official" migration, but they eventually gave up too as even the oldest backup archives they could find had the same issues.
The exception being obviously a team approaching someone else's codebase -- including that of their predecessor, if they can factor in for Conway's Law -- to re-factor it.
But the same person or persons announcing re-factoring? I always try to walk away from those discussions, knowing very well they're just going to build a better mouse trap. For themselves.
Don't get me wrong, iteration of your own then-brain's product is all well and good, but it takes _more_ to escape the carousel. It takes sitting down and noting down primary factors driving poor architecture and taking a long hard look in the mirror. Not everything is subjective or equivalent, as much as many a developer would like to believe. It's very attractive to stick to "as long as we're careful and diligent, even sub-optimal design can be implemented well". No, it won't be -- this one is a poster-child exception to the rule if there ever was one -- your _design_ is the root and from it and it alone springs the tree that you'll need to accept or cut down, and trimming it only does so much.
A panacea is a cure-all. So if code refactoring is a panacea then we should refactor code often.
$ what /usr/bin/file
/usr/bin/file:
PROGRAM:file PROJECT:file-106
$File: apprentice.c,v 1.309 2021/09/24 13:59:19 christos Exp $
$File: apptype.c,v 1.14 2018/09/09 20:33:28 christos Exp $
$File: ascmagic.c,v 1.109 2021/02/05 23:01:40 christos Exp $
$File: buffer.c,v 1.8 2020/02/16 15:52:49 christos Exp $
$File: cdf_time.c,v 1.19 2019/03/12 20:43:05 christos Exp $
$File: cdf.c,v 1.120 2021/09/24 13:59:19 christos Exp $
$File: compress.c,v 1.129 2020/12/08 21:26:00 christos Exp $
$File: der.c,v 1.21 2020/06/15 00:58:10 christos Exp $
$File: encoding.c,v 1.32 2021/04/27 19:37:14 christos Exp $
$File: fsmagic.c,v 1.81 2019/07/16 13:30:32 christos Exp $
$File: funcs.c,v 1.122 2021/06/30 10:08:48 christos Exp $
$File: is_csv.c,v 1.6 2020/08/09 16:43:36 christos Exp $
$File: is_json.c,v 1.15 2020/06/07 19:05:47 christos Exp $
$File: is_tar.c,v 1.44 2019/02/20 02:35:27 christos Exp $
$File: magic.c,v 1.115 2021/09/20 17:45:41 christos Exp $
$File: print.c,v 1.89 2021/06/30 10:08:48 christos Exp $
$File: readcdf.c,v 1.74 2019/09/11 15:46:30 christos Exp $
$File: readelf.c,v 1.178 2021/06/30 10:08:48 christos Exp $
$File: softmagic.c,v 1.315 2021/09/03 13:17:52 christos Exp $
$File: file.c,v 1.190 2021/09/24 14:14:26 christos Exp $
...
WHAT(1) General Commands Manual WHAT(1)
NAME
what - show what versions of object modules were used to construct a file
SYNOPSIS
what [-qs] [file ...]
DESCRIPTION
The what utility searches each specified file for sequences of the form
"@(#)" as inserted by the SCCS source code control system. It prints the
remainder of the string following this marker, up to a NUL character,
newline, double quote, `>' character, or backslash.
The following options are available:
-q Only output the match text, rather than formatting it.
-s Stop searching each file after the first match.
EXIT STATUS
Exit status is 0 if any matches were found, otherwise 1.
SEE ALSO
ident(1), strings(1)
STANDARDS
The what utility conforms to IEEE Std 1003.1-2001 ("POSIX.1"). The -q
option is a non-standard FreeBSD extension which may not be available on
other operating systems.
HISTORY
The what command appeared in 4.0BSD.
BUGS
This is a rewrite of the SCCS command of the same name, and behavior may
not be identical.
macOS 26.4 December 14, 2006 macOS 26.4At any rate, the original link was
https://hackingpassion.com/fast16-pre-stuxnet-cyber-sabotage...
Which while apparently being AI generated, does have some additional information over the other sources. (Which have apparently also been deleted from the thread.)
For example it makes a reference to this relevant paper, though it fails to cite it properly.
https://onlinelibrary.wiley.com/doi/10.1155/2024/1672269
---
Another great source for the story is:
https://www.theregister.com/2026/04/24/fast16_sabotage_malwa...
And in case it changes again, the current link is:
https://www.sentinelone.com/labs/fast16-mystery-shadowbroker...
Which is a write up by the actual researchers.
https://bazaar.abuse.ch/sample/9a10e1faa86a5d39417cae44da5ad...
I'll probably build a Windows XP VM first.
The modern equivalent may be something like {insert adversarial country name here} downloading a pirated version of Ansys Autodyn 2026 R1 shortly after official release from a Chinese cracking group on a Chinese bulletin board forum, where just a handful of seeders sit behind Russian ISPs. And then {insert adversarial country name here} later notice during experimentation that the software calculations never quite match experimental results, and maybe then suspecting the pirated copy was deliberately tampered with and distributed. However, this situation may be fairly easily solved by {insert adversarial country name here} by just grabbing a copy of the software they want off a hacked network of a random university or engineering consulting firm in the aerospace and defence sector. Plus it may be naive to assume {insert adversarial country name here} in 2026 couldn't develop their own software from scratch (and/or perform calculations manually), or just rely on experiments, to achieve whatever outcome some other nation state group of hackers is trying to avoid. {insert adversarial country name here} would have to have experimentation equipment and skills regardless to verify manufacturing quality. Simulation software mostly reduces costs and timeframes by reducing the number of mockups and physical experiments needed. For example, it's cheap to run 1000 simulations of an artillery shell hitting vehicle armor plates as shown in [3], and more expensive and time consuming to do the same repetitive thing in the real world.
[1] https://ftp.lstc.com/anonymous/outgoing/jday/manuals/LS-DYNA...
Very good book. Perhaps a follow up series will be needed with the new information coming out and of course what we have seen/learned since.
I also wonder why they opted to make this an injectable worm and not just a side-loaded 'feature' of the OS?
But indeed many more details in the link you shared. Thanks for posting this!
I was about to respond saying what a terrible article it was, as it reads as if the author has no idea what he was talking about. Attempting to paraphrase the original article would explain it.
Edit: Old link for those wondering, since it got changed: https://hackingpassion.com/fast16-pre-stuxnet-cyber-sabotage...
https://www.theregister.com/2026/04/24/fast16_sabotage_malwa...
This LLM style of writing has had it's day.
(@dang - consider re-pointing to this?)
The current article is hard to read
This one has some additional details, based on a talk given by one of the authors.
They are improving like crazy on clear energies and the Oil Jihad can't do nil.
This comment is very exaggerated, I can think of a few more "morally corrupt" things to do.
Obviously it was found by a mathematician, but I still suspect it wasn’t obvious in published research or that it ended up not causing significant enough deviations to cause research to revisit the calculations.
My team ran into some interesting but very small deviations when we moved our iterative solar wind model from 32 bit to 64 bit, but the changes weren’t significant enough to revisit or re-do prior research wholesale.
Like my team in the 2000s I suspect anyone who had data crunched by this bug also revisited it and either concluded it wasn’t significant enough or redid the work and it didn’t change the conclusions.
I am curious now if this bug was cited in any papers at the time to give a rough idea how aware or affected academics were.
We had researchers doing what I suppose might be called HPC on Sequent Symmetrys, which were i386s in the mid-80s and Pentiums by the mid-90s. There were other high-performance x86 SMP boxes that were roughly equivalent (e.g. NCR 3550). That plus some pretty good x86 FORTRAN compilers (e.g. Lehey (sp?)) made this reasonable. I also know a lot of folks who had desktop/side SMP PPros + FORTRAN to save grant money on the big iron and got useful work out of them.
Basically, x86 was way cheap and had useful amounts of FP. There's a reason x86 displaced risc; this is one. I'm sure they would have rather used something like an X/MP-48, but one plays the hand one is delt.
And yes, to be clear, I don’t consider it contributing to “science” if it’s not published, reviewed, and reproducible.
[1] https://en.wikipedia.org/wiki/Assassinations_of_Iranian_nucl...
Shitty and brainwashed people in Middle East comes in both ways.
Can't wait to the Chinese secularizing all the Abrahamic bullshit by brute force -not by war, but my mere productivity and good reasoning- throwning all the Abrahamic legacy to the dust bin. So, y'all think you are the center of the world, Mediterranean fools? The Chinese got everything you brag from Math in the same way (basic algebra, proto-integration). And, if any case... the Egyptians were before any Abrahamic nonsense. Heck, the Exodus was just a primitive form Nationalist brainwashing, a la North Korea. So, the days for the Mediterranian Jingoism -and oil, of course are numbered the day the Chinese set a working fusion reactor.
Obviously IOCs are presented.
We will probably keep doing it until we encounter an alien intelligence and snap out of it.