How to open this screw

These screws are commonly used in cheap consumer goods where safety is a concern, for example electrical equipment such as extension strips.... They are indeed intended to be done up only, specifically to discourage end users from dismantling equipment and possibly becoming black and crispy during the process.

Trying to recover the socket strip is false economy. By the time you've researched various methods of obtaining access and purchased or fabricated whatever tools are needed to remove these screws, you will have spent enough money to buy several new strips, to say nothing of your time.

@Gerwin Jansen:

I also assume that the asker would disconnect from the power before proceeding, but manufacturers do tend to err on the side of caution!

However, in regard to the hidden wonders of the strip's interior I would not expect to add significantly to my knowledge by exposing them to the light of day. More complicated stuff, definitely worth a look, but... a socket strip?

I do not want to invest in new tools. It makes no sense, becomes to expensive for nothing.
I used it for a while and now has no more output power.
I realized that type of one way screw is done intentionally to protect against unauthorized persons to be opened.
It is not a problem of safety for me, as I work with electricity daily up to 1500VAC...so 230Vor 400Vac is normal business for me...the safety is not a concern here. I just wanted to have it open and see if I can repair it and of course in the end to install other types of screws.
I tried to drill the heads using HSS gold drill bits, but it does not work, are so hard material as steel...
It is a nice extension cord, aluminum case, surge protection function...it is this one:
https://www.bachmann.com/en/products/it-power-distribution/it-pdu-basic-1-u/
If I could just get one screw out, then one nice suggestion above was to use the head of that screw for the other 3, because are 4 in total.
I tried all kind of normal screwdriver, bigger and smaller with force, even before I asked the question here, but no luck.
The suggestions above are nice, but I do not have the tools, but I will ask some friends around....

By the way, I have a special tool set of screwdrivers from PROXXON INDUSTRAIL:
https://www.proxxon.com/en/industrial/23107.php
There are "claw keys", but they just  ride up on the curved surface of the security screw similar as a normal screwdriver.
There are also "3 Clutch sockets: C1, C2, C3", but are too big for the head of the screw.

And just an aside note, my extension cord is "BACHMANN 19´ Steckdosenleiste, 1-HE, 6-fach, 333.402" which costs around 75-80€.

>>    but they just  ride up on the curved surface of the security screw   <<  that's why i posted   and apply force.

This extension cord was not used anymore for IT purpose. Since years was thrown in a corner and no one used it. Was to be sent in garbage when the company moved. It worked fine at that time, but I used it for my home electrical oven :) and in 6 months did not work any more...so, only because seemed nice and solid I wanted to repair it, but has nothing to do anymore with IT, servers...

...and I applied "brute force attack", but does not want to be cracked, has a strong password :)

Here are the small drill bits HSS that I have used, but no luck, the material is too hard and the drill worn out.

Then, trying to force each of the 4 screws, I “succeeded” to unscrew a bit one of them, 1-2 turns and then is stuck in that position, but I tried I used a mini hacksaw thinking that if I cut the head of one screw, then I may use to unscrew the other 3. Again bad luck, the hacksaw cannot cut that screw, the material is just too hard, I do not know what kind of steel is it.

In mean time I said to myself „let's try one more time “and as result I broke one 2mm drill bit and I destroyed one new hacksaw blade.
I think is more a question of pride: me or the screw :)
The screw won until now.
I started to understand why they make it 80€, even if it is not the right price for such cord.
In parallel with your answers, I have read on internet some other similar experiences and when I saw the method from here:
https://www.doityourself.com/forum/hardware-fasteners/208462-removing-one-way-screw-tip.html
using a center punch and a hammer, was like an epiphany, I already seen them all 4 unscrewed in mind :) , then after some minutes I had to come back to reality, because it did not work for me that method. Maybe if the screw in on the wall or wood, but as in my case, being in aluminum tightened and with plastic around the head, it does not work.
I think I will give up.
Only with the special tool seems that will work out to unscrew it, otherwise is lost battle and lost time.
By the way, my last question: how many of you, except nobus in a happy single case, have really dealt with suck kind of screws in reality and really successfully unscrewed such kind of screws and did not only read on internet about the possible solutions?
If there is no answer, I take it as not dealing in reality with it.
I just need to raise my pride up a bit :) and to know to whom shall I assign the points :)

is that where the saying comes from ' he gets screwed"?

"Easy Out" is the most amazing misnomer for a "tool."  I've got them but I've never seen one work.  Not once.  Now I just weld a hex bolt on and avoid the time-wasting side trip.  However, in this case that's not an option.

You might try a Dremel-type rotary tool with a the smallest diamond cutoff blade you can find.  This will allow cutting off the screw head while minimizing damage to the surrounding area.  Be sure to cut the head off as close to the head as possible, because you'll still have to turn out the remains of the screw shaft with a pliers which means there has to be enough of the shaft exposed to grip.

If you have a Dremel type rotary tool, use the cutter to cut a groove into the screwdriver slot. This groove can then accept a standard flat blade screwdriver.

Oh ... doin' it the easy, obvious way.

Well, I suppose you could do that.

I have Dremel, but there is no chance to use it. There is no space to cat the heads. I would just destroy the plastic of the extender. The Dremel is useless, of course I was thinking at it, because i use it often. Don't you see the photos above?
I just put it aside in a corner until I will get the proper tool and if too long time will pass then has only one place: will land in the garbage where it belongs.

Thank you for all your suggestions and shared experiences.

i remember spending some time on it, not easy at all
several screwdrivers and tries were needed + force (to keep the screwdriver on the bottom of the screw, and not sliding up

Might be worth trying an impact driver on it. there is a lot of downward force as well as a bit of lateral force with these.

Put a small torch on it and pull it right out of the plastic!

Indeed. Small torches are cheap (although how you get a screw out with them I don't know)

https://www.eurocarparts.com/ecp/p/car-accessories/summer-essentials/car-accessories/gifts/?548779040&0&cc5_1051&