Zen Backpack Security - Slash Attacks






Backpack Security - Slash Attacks


Slash Attacks

Slash and Snatch Protection

Slash and Open Protection


Also See:

Backpack Security

Locking Up Your Backpack

Slash Attacks

Choosing the Right Backpack

Personal Security


Slash Attacks

Although not a wide spread attack technique, many thieves have been know to slash straps on bags and run, or even slash open backpacks when left unattended or even when on your back or sitting next to you.  Slashing is difficult to defend against, but there are several tips, modifications and special gear which can drastically reduce your vulnerably to this security threat. 


One of the unique problems with a slash attack is that even failed attempts at theft are problematic.  Even if a slasher doesn't get away with any belongings, the damage incurred by your pack really sucks, particularly if they damage your zipper or cut the Gortex jacket in your pack. 



In addition to sharp knives, razor blades and utility knives, some thieves have been known to use scissors.  Some scissors will cut through specialty cords (e.g. Kevlar and Spectra) or even through thin metal cable used on "slashproof" straps, security packs and some locks.  So the goal of slashproofing generally means making your pack "cut resistant" and not truly "cut proof".



Slash and Snatch Protection

One type of mugging technique includes the slash and grab.  The assailant will slash a critical strap or belt and run away with your bag.  You can decrease the incidence of this happening by using a backpack instead of a single strapped bag or fanny pack.  A shouldered purse is a tempting target in itself and a hand carried one is an invitation for theft.


There are a few general approaches to dealing with this potential threat:

  1. Use a backpack, preferably with hip belt instead of single strapped bag.  This makes you a much less desirable target for this type of attack over other targets with single strapped bags.

  2. Don't worry about this sort of attack.  It is rare and generally avoided with simple street smarts.  You can recover from theft.

  3. Walk around paranoid clenching your bag/pack while in crowds

  4. Slashproof your strap(s) - particularly if you only have/use one strap

  5. Ignorance

  6. Don't travel


Adding stainless steel cable to a strap will make it difficult to cut

This is great for fanny packs, bags with a single shoulder strap and waist belts


The more straps you have on (shoulder and waist straps), the more difficult it is to remove a pack/bag from your body.  Single shoulder strapped bags are less secure than those with 2 or 3 straps (counting your hip belt or sternum strap).  Protection against snatching with a single strapped bags is increased by wearing the shoulder strap diagonally across the body instead of wearing it vertically over one shoulder.  When a fanny pack or single strapped bag is used, it is a good idea to add a metal cable to the strap or at least replace the strap with a thick heavy duty one to make it more difficult to cut. 


Bags with a single shoulder strap should use a strap reinforced with steel cable to prevent slash and grab attacks

Purses should use slashproof cables or preferably not be used

Thick leather and metal chains have been used in some bags are are very cut resistant


Companies such as Pacsafe and  Travelon make bags with steel cables already built into their straps.  Their backpack designs may not not match up with your idea of a perfect pack, but their fanny packs, bags with single straps and accessory straps are certainly worth looking into.


European Patent 2064967A2


Chain link shoulder straps are pretty slashproof

These bags are far too flashy to carry, but you get the idea


Slash-proofing a single strapped shoulder bag is generally reasonably easy to do, particularly since you can purchase Slashproof straps.  And although slash and grab theft is uncommon in most parts of the world, a "slash-proof" strap might give you a little more piece of mind and perhaps an interesting DIY project. 


These and similar strap designs allow for use of thick leather, thick webbing and steel cable reinforced straps


Trying to slashproof the straps on a conventional backpack with 2 shoulder straps can be challenging since steel cables don't bends as easily as plain fabric straps.  Understanding the challenge, there are a few ways to make shoulder straps cut proof if you want to.



Some PacSafe backpack straps incorporate straps with a steel cable.  European Patent 1941812A1

The strap is routed through a sleeve or multiple sections of webbing on the upper shoulder strap so that a portion of strap without steel cable can be routed through a tensioner at the top of the shoulder strap.   This allows for a "slashproof" strap which can still be easily adjusted each time you put on your pack.


Slash proofing options for backpack with dual shoulder straps:

  1. Use of straps with steel cables sewn in or thick cut resistant straps generally don't like the strap tensioners used on most backpack straps.  These less flexible straps can be fitted to a backpack in a number of ways, but generally only allows for minimal adjustment.  This isn't ideal of heavy packs, but may be acceptable for some applications.

  2. Kevlar Straps - These are extremely cut resistant compared to nylon straps and when thick enough are difficult to cut with a quick slash of a knife.  These are used by firefighters because Kevlar has excellent heat resistance for a fabric.  The problems with Kevlar is that it absorbs water and is prone to damage from sunlight.

  3. UHMWPE—Ultra High Molecular Weight Polyethylene aka Spectra and Dyneema - These are slippery, strong and cut resistant fabrics.

  4. PacSafe backpack strap idea (see image above).  Slackproof a special shoulder pad with a steel wire.  Instead of running a tensioning strap through a strap tensioner at the bottom of this shoulder pad, install a strap tensioner at the top of your shoulder strap.  Then run the shoulder strap webbing through the bottom of the shoulder pad and tunnel it through the shoulder pad so that it comes out at the top of the shoulder pad where you positioned your strap tensioner.  Since the shoulder pad protects the strap webbing from a slash attack, you only need to slashproof the lower part of your shoulder straps.  Leave a sufficient amount of the upper strap bare so that you can tension your strap.  This allows you to tension your strap while having a reasonable amount of protection to your exposed straps.

  5. Slashproof the waist belt only.  This is much easier to do and allows you to keep your regular shoulder strap setup.  You can simply add a metal cable or chain to each side and link them in the middle.  You can also replace the belt with something that looks more like an oversized trouser belt, which would be better suited for heavy duty material, leather or a steel cable reinforced webbing than the traditional side release setup used on most backpacks.

  6. Retractable chain:  Use a chain with shockcord (elastic) to create a retractable knife barrier.  This can be used on your hip belt or even your shoulder straps.  Shockcord can be woven through the chain or the shockcord and chain can be covered with nylon tubing to conceal, protect and limit jingling to some extent.

  7. Add "lanyard" to pack and attached backpack to your trouser belt.


Quick release snaps on fanny packs can either be concealed/protected with a cover and/or augmented with a lock/locking carabineer to make it a bit more difficult to unfasten.  These can also be replaced with lockable buckles or other fastening systems which are more difficult to unfasten.  The strap on fanny packs (with or without a steel cable) can also be looped through belt loops and/or around your belt to make it more difficult for someone to unsnap or cut them and run.  It is important to note that depending on how you route your strap, this can make going to the bathroom a bit more difficult - especially in an emergent situation.  You can also add well attached loops to your bag so that your can run your trouser belt through them for a second layer of fixation.


Coiled lanyard designed for pistol security



One end of a lanyard (aka "dummy cord") can be attached to your pack and the other end to your pants' belt so that if anyone grabs your pack from you, they'll have to pull you along with your pack.  This can be a bit annoying at first, but protects your bag from Grab-N'-Run thieve whenever you take your pack off (such as to when you need to get something from it or when taking it off to sit down).



Slash and Open Protection

It is sad knowing that no matter what sized lock you have on your backpack, most backpacks can be opened up with a razor or utility knife faster than you can unzip your bag fully open.  This is sometimes done by thieves in crowds at train stations or in busy night markets.  It is also a potential threat to gear left behind in rooms and hostels or even gear secured next to you while you doze off to sleep or when you are distracted on your electronic device.  Despite this being an uncommon technique, it is difficult to defend against this sort of attack and bitterly painful when you become a target.


Pelican 1510 Hard Case - slashproof and waterproof


The best protection against this type of attack if staying vigilant, packing items of value deep in your backpack and close to your back and perhaps wearing your pack in the front of your body.  And if you plan to leave gear behind of reasonable value for extended periods of time, you might want to consider using a lockable hard case without zippers and securing it with a real lock and cable.


Pacsafe Daysafe 200 with slashproof metal mesh


"Slash-proofing" fabric bags can be helpful against knife attacks, but even most of the well engineered, commercially produced, "slash-proof" packs have weak points - such as at the zippers.  There are a few luggage type bags built with thick enough material to defend against most slash attempts, but they tend to be heavy and bulky and better suited for luggage carousels than for extended all day backpacking. 







Heavy Leather is hard to cut open quickly and has was even been worn as armor in the past to protect against edged weapons


DIY slashproofing a pack is an option for the creative but difficult to do.  The goal is to either use thick enough material to slow slashing, or to use cut resistant material like metal cable and plastics to to stop/slow cutting.


Salomon Experience Pack


Many luggage type packs have semirigid backs and/or sides that incorporate a foam or plastic layer under a heavy duty nylon layer.  Made to protect the pack's contents from the rigors of airport baggage handlers, they are often thick enough to resist a quick slash and open.  Unfortunately, these packs tend to be overbuilt and too heavy for comfortable and extended backpacking use. 


Flexible cutting boards are by design cut resistant


DIYers can sew on thick nylon webbing in a mesh pattern or add foam or thin plastic (flexible cutting board) to the inside of their packs to slow or stop slashing.  A rolled up foam pad or thin plastic sheet can add a bit of impact and slash protection to the contents of a top loading pack.


YouTube  kBfVABIoYsU Plastic cutting board protection


Spectra Webbing

Spectra Webbing


Cut resistant materials such as Spectra (Ultra-High Molecular Weight Polyethylene) and Kevlar will quickly dull knives and scissors and if thick enough, will prevent a hastily executed slash attempt.  "White Widow" nylon with Spectra ripstop cords will not stop a fresh utility blade from making a nice long cut.  On the other hand, 100% Spectra webbing sewn onto a pack in a mesh pattern will stop most successful slash and open attempts.  This can be pricy, will add some weight to your pack and is very labor intensive.


The Ursack bear bags (Spectra or Kevlar) will stop a bear from ripping through them

These may stop a knife attack and can be used to line the inside of a backpack or even used to make the body of a custom backpack


Kevlar is pretty cut resistant but can be difficult to work with.  If used, it is often better to sandwich it in between two layers of fabric rather than using it as an outer or inner layer of a pack.  It also soaks up water and is very prone UV damage from the sun. 


McHale Dyneema. UnLtd +1

McHale Dyneema. UnLtd +1 with 2 layer Summit Pack


Dyneema, like Spectra is Ultra-High Molecular Weight Polyethylene and differs only on how it is processed (extruded vs gel spun).  It is used in sails, fencing suits and McHale Packs in Seattle Washington can make a custom alpine pack with this and other materials.  Likewise, a DIYer with a lot of time an funds can make a very durable and cut resistant pack out of Dyeema.


Stainless Steel Slash-Proof Pack

30L Daypack with 50feet of 1/32" stainless steel 7x7 cable sewn to outside of pack


Flexible stainless steel cable sewn onto a pack will stop cutting with a razor or utility knife and either slow or stop cutting with scissors.  This is really difficult to custom modify a pack in this manner - but is doable if you have the time and energy to do so.  Fine jeweler's flex cable can be interwoven into the fabric itself, while larger diameter cable (1/32") can be either tacked down to the pack with some stitching, covered in narrow webbing, tape or hollow cord (parachute cord) and sown to your pack.  Again, Pacsafe and  Travelon makes a couple of products with steel mesh in them.


wateringhole.gadventures.com  9751 - discussion of aircraft cable and plastic snow fence



If you are shopping for flexible cable, make sure that it is 100% stainless steel or titanium for strength, durability, and weather resistance.  Cables made with many fibers (7 strands of 7 strands - aka 7x7 or more) are generally more flexible than those made with fewer fibers (3).  Appropriate cable and wire can be found at hardware, steel specialty, bead and fishing shops/stores.  Brake/shifter cables for bicycles can also be used.


Stainless steel chains can also be used.  They are more expensive and heavier than cable, but can look nicer than cable if you are looking for that special "chained up" look.  Chain also doesn't fray like cable at spots where there is a lot of repeated bending.



Stainless steel mesh (chicken wire) can be used to line the inside of purses or satchel bags.  Because of the stiffness of this material, it isn't ideal for backpack use.  It can also be difficult to work with due to the potential of having a great many sharp ends, but these can be covered up with duct tape, ballistic nylon or other means.





Pacsafe makes a wire mesh made of 1/16" stainless cable designed to wrap around a pack like a fishing net.  This offer some protection and will potentially deter most would be thieves, but may also get their attention.  These are not light and do take up some space in your pack when not in use.  When is use, it also makes it difficult to access your gear.  In most places, these are not very practical but are an option worth considering for the truly paranoid who don't have the time to customize their pack or use a hard case.


US Patents for metal mesh security devices:










2022251 - metal gauze and more

2416747 pasted-seams





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