Featured Post
Practical Security Recommendations for Start-ups with Limited Budgets
Hi, my name is Alex, I’ve been an IT security professional since 2007 and I’ve recently entered the start-up world with my project bughuntr.io. In putting together this project, security has been a primary concern for me. This is both due to my background and the nature of the project, being a training platform for security professionals and enthusiasts alike. In my security career, I’ve been hired to assess countless web applications, cloud environments and computer networks for security vulnerabilities. In these assessments, it is always clear when security is ‘bolted on’ as a compliance requirement before releasing a product, or added at a later date in response to an incident. Start-ups have a rare opportunity to ‘bake’ security in at the start of a project, but this is often seen as an expensive endeavor. In this post, I aim to ease that fear and provide practical (and cheap) advice for start-ups who want to release a more secure product right from the start.
BitBucket Pipelines Kata Containers Virtual Machine Escape
Atlassian ran a project on Bugcrowd looking for bugs in their proposed implementation of Kata Containers within the BitBucket Pipelines CI/CD environment. Whilst participating in this project, I identified a vulnerability in Kata Containers which could allow processes running in the Kata VM to write to supposedly read-only volume mounts. This vulnerability was fixed by the Kata Containers team and assigned CVE-2020-28914. Within the project Pipelines environment exploiting this vulnerability allowed a malicious build job to write semi-controlled data to arbitrary files on the host system as the root user.
The following is an account of the discovery of this bug and an assessment of the impact of exploiting the bug in the project BitBucket Pipelines environment.
Note: This post originally appeared on Bugcrowd’s blog it is re-posted here as the Bugcrowd post has suffered some format mangling and has been truncated, this appears to have occured during a blogging platform migration.
Privileged Container Escape - Control Groups release_agent
I’ve recently been doing a lot of bug hunting in containerized environments, and one common theme has been escaping a container to execute code on the container host. In this post I’ll expand on a technique reported by Felix Wilhelm (@_fel1x) to escape a privileged container to execute arbitrary commands on the container host.
GitLab - Importing GitLab project archives can replace uploads of other users
HackerOne bug report to GitLab: Importing a modified exported GitLab project archive can overwrite uploads for other users. If the secret and file name of an upload are known (these can be easily identified for any uploads to public repositories), any user can import a new project which overwrites the served content of the upload with arbitrary content.
44Con 2019 - Continuous Integration Continuous Bounties
CI/CD pipelines are the perfect, bug-rich target for new and experienced bug hunters. As complex, user-controlled automated processes with access to authentication secrets, source code, and application servers in multi-system, multi-user environments, they combine all the things that make bugs likely. In the presentation, I will outline a methodology for hunting for bugs in CI/CD pipelines and walk through actual bugs which have resulted in tens of thousands of dollars in bounty payments.
Exploit Archeology - Exploiting an old unknown Server Side Browser
I was recently hacking on a Bug Bounty target and identified an interesting API endpoint which would render user supplied HTML, and execute any included JavaScript. Exploiting Server Side Browser bugs has been a focus of mine for the past couple of years, so I set out to exploit this newly identified feature. This blog post details my journey into researching and exploiting what turned out to be a decade old Server Side Browser.
Critical Thinking Episode 31: Alex Chapman - The Man of Many Crits
Practical Security Recommendations for Start-ups with Limited Budgets
Hi, my name is Alex, I’ve been an IT security professional since 2007 and I’ve recently entered the start-up world with my project bughuntr.io. In putting together this project, security has been a primary concern for me. This is both due to my background and the nature of the project, being a training platform for security professionals and enthusiasts alike. In my security career, I’ve been hired to assess countless web applications, cloud environments and computer networks for security vulnerabilities. In these assessments, it is always clear when security is ‘bolted on’ as a compliance requirement before releasing a product, or added at a later date in response to an incident. Start-ups have a rare opportunity to ‘bake’ security in at the start of a project, but this is often seen as an expensive endeavor. In this post, I aim to ease that fear and provide practical (and cheap) advice for start-ups who want to release a more secure product right from the start.
GitLab AMA - Bug Bounty with Alex Chapman
BitBucket Pipelines Kata Containers Virtual Machine Escape
Atlassian ran a project on Bugcrowd looking for bugs in their proposed implementation of Kata Containers within the BitBucket Pipelines CI/CD environment. Whilst participating in this project, I identified a vulnerability in Kata Containers which could allow processes running in the Kata VM to write to supposedly read-only volume mounts. This vulnerability was fixed by the Kata Containers team and assigned CVE-2020-28914. Within the project Pipelines environment exploiting this vulnerability allowed a malicious build job to write semi-controlled data to arbitrary files on the host system as the root user.
The following is an account of the discovery of this bug and an assessment of the impact of exploiting the bug in the project BitBucket Pipelines environment.
Note: This post originally appeared on Bugcrowd’s blog it is re-posted here as the Bugcrowd post has suffered some format mangling and has been truncated, this appears to have occured during a blogging platform migration.
Daily Swig - Container security: Privilege escalation bug patched in Docker Engine
A vulnerability in a Docker Engine security feature potentially allowed attackers to escalate privileges from a remapped user to root.
“The two avenues of exploitation I found would allow writing of arbitrary files as the real root user” or seizing ownership of files previously accessible only by the root user, security researcher Alex Chapman, who unearthed the flaw, tells The Daily Swig.
Moby - Access to remapped root allows privilege escalation to real root
In Docker before versions 9.03.15, 20.10.3 there is a vulnerability involving the –userns-remap option in which access to remapped root allows privilege escalation to real root. When using “–userns-remap”, if the root user in the remapped namespace has access to the host filesystem they can modify files under “/var/lib/docker/
Kata Containers `hostPath` file write
Bugcrowd bug report to a Private Program: Kata Containers was found to be vulnerable to an issue allowing Kata VMs to write to hostPath mount points which should have been read only. This issue was fixed in the Kata Containers project and assigned CVE-2020-28914.
Privileged Container Escape - Control Groups release_agent
I’ve recently been doing a lot of bug hunting in containerized environments, and one common theme has been escaping a container to execute code on the container host. In this post I’ll expand on a technique reported by Felix Wilhelm (@_fel1x) to escape a privileged container to execute arbitrary commands on the container host.