diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -489,7 +489,7 @@ First things first: Docker runs as root. If you are in the `docker` group, you e
 
 Docker should not be your only defense. You should secure and harden it.
 
-For an understanding of what containers leave exposed, you should read is [Understanding and Hardening Linux Containers](https://www.nccgroup.trust/globalassets/our-research/us/whitepapers/2016/april/ncc_group_understanding_hardening_linux_containers-10pdf) by [Aaron Grattafiori](https://twitter.com/dyn___). This is a complete and comprehensive guide to the issues involved with containers, with a plethora of links and footnotes leading on to yet more useful content. The security tips following are useful if you've already hardened containers in the past, but are not a substitute for understanding.
+For an understanding of what containers leave exposed, you should read is [Understanding and Hardening Linux Containers](https://www.nccgroup.trust/globalassets/our-research/us/whitepapers/2016/april/ncc_group_understanding_hardening_linux_containers-1-1.pdf) by [Aaron Grattafiori](https://twitter.com/dyn___). This is a complete and comprehensive guide to the issues involved with containers, with a plethora of links and footnotes leading on to yet more useful content. The security tips following are useful if you've already hardened containers in the past, but are not a substitute for understanding.
 
 ### Security Tips