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How to Bypass a Wire Cable Seal - Tamper Evident Bypass

Hey there Mos and Boo fans.  I'm Mos and in this video I’m  

going to show you how to bypass  a wire cable seal using a needle.  

I’m also going to pull one apart so you can see  how they work and why this bypass is so effective.

Let’s get started!

In our last tamper evident bypass  video I showed you how to bypass  

a fixed length seal. I also briefly showed  you a green wire cable seal. I thought some  

of you might be curious about how to bypass this  type of seal so we decided to make this video.

A cable seal isn’t fixed length  like the last seal we bypassed.

You put one end of the cable through the  body of the seal and then pull it tight,  

just like a zip tie.

Once the cable goes into the  body, you cant pull it back out.  

It only goes one way. I’ll explain why in a bit.

Here I have three different  types and sizes of cable seal.

The main difference is they have different  

thickness cable so they have  different breaking strengths.

The cable is usually made of  braided aircraft cable. This  

makes it very strong and if you cut  it, it will splay out making it pretty  

much impossible to rejoin without  looking like its been tampered with.

So if you were thinking of cutting  it and feeding it back into the body,  

it’s probably not going to work.

We know for a fact that this  cable splays out when cut.

Back at BSides Canberra 2018, a couple  of people cable sealed their own wrists  

before finding out if they could bypass the  seals. No one could. No one had cutters.  

All anyone had were metal files so they  spent two days filing themselves out.

Don’t believe me? Here you go!

And now there are warnings signs at  all the security conferences since.

If you look at the cable seal body, they are  usually aluminium and have serial numbers on them.

This is so you cant just cut the seal  and replace it with the same type.

In the body there is a hole where one  end of the cable is attached permanently.

You will also notice there is another piece  of metal inserted in the middle of the body.

This is the locking mechanism for the cable.

You will see there is a second hole that  runs along the edge of this metal insert.  

This is where the cable gets fed into  the body when you want to lock the seal.

This piece of metal is permanently  attached using different methods.

One attack would be to pull this piece of metal  out, which would let you remove the cable.

This is possible on some cable seals but not all.

If you look at these two, you can see the  body has been squashed onto the cable,  

so you would have to destroy  the body to release the cable.

On this third one, you can  see that there is a single  

hole that is filled with some sort of metal.

It actually looks like solder in this hole.

I only have one of these and wanted to show it to  you first so after I film this bit of the video  

im going to go get a blowtorch out and see if I  can melt this bit of metal and remove the plug.

Ok.. that didn’t work. But that’s the best part  about tamper evident bypassing and lock picking.  

Coming up with theories then  experimenting and breaking stuff!

Seeing that didn’t work I drilled it out instead  

so we could remove the centre piece  and show you the locking mechanism.

This is pretty cool. Looking at the  centre piece you can see this little  

barbed wheel next to a piece of spring steel.

When you push the wire in, it pushes the  wheel down the hill and against this spring.

The spring compresses letting the wheel  go down further and the wire to slip past.

When you try and remove the wire by pulling  backwards, the barbs grip the wheel pulling  

it up the hill jamming the wheel and the  wire against the roof of the seal body.

Thats why you cant pull the wire out.

It’s a really clever design. Nice work  little wheel dude! But im tricksier than you.

To bypass the seal we need to make  sure the wheel cant roll back uphill.  

Luckily the little wheel has a small  channel to let the cable slide over it.

And guess what fits perfectly into this channel?  

This needle.. which Im definitely  not storing in my pants. Ouch!

To bypass the seal, we can slide a  needle along this channel and force  

the wheel back down into the spring and make  a smooth bridge for the wire to slide over.

Let’s show you this technique in action

All you have to do is slide  the needle in under the cable.

It needs to be from the side you slid the cable  in so the cable slides out along the needle.

When you put the needle in you can  feel the wheel and the little channel.

It can take a few goes as the needle often  slides out to the side as you pull the cable  

out but after a few goes the cable is  fully out and you’ve bypass the seal.

You can now open whatever it was sealing  and then put it back and no one will know.

Just a note. This attack  won’t work on all cable seals.

It works well on these small ones cause of the  

size of the wheel and the gap  between the body and cable.

We will be ordering a bunch of test seals soon so  

will make another video on  how to bypass those ones.

If you want to learn more ways to bypass  tamper evident seals and other physical  

controls, make sure you subscribe  to our YouTube channel and also  

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We would love to hear from you in the  comments so if you have any comments  

or have ideas for any videos you  think we should do, let us know.

Until then, we will be back soon  with another tamper evident bypass!