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Questions tagged [capabilities]

A capability is a set of access rights granted to a subject, often transferable. Capabilities are a method for access control.

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Container escape - CVE-2022-0492 - hybrid cgroups?

I saw the recent CVE-2022-0492 that can enable container escape, and I have a decent understanding of cgroups and container capabilities, but not very familiar with how hybrid cgroup v1/v2 works, nor ...
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0 answers
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Playing with cap_dac_read_search, but still unable to read /etc/shadow

I'm playing around with capsh and cap_dac_read_search capability, on a Ubuntu 20.04 machine (kernel version 5.4.0) In theory the nobody user can read /etc/shadow if I gave cap_dac_read_search ...
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2 votes
1 answer
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What additional protection does seccomp provide when compared to capabilites?

From this answer I understand that seccomp-bpf filters the list of syscalls a process can call. Similarly, the capabilites mechanism will cause a syscall to fail if the caller does not have the ...
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4 votes
1 answer
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Privilege escalation writing /etc/passwd but without SUID permission on su

This is not an exercise, there might be no solution. We are producing a Docker image (based on CentOS) which is designed to be executed by a non-root user. However, this user has write access to /etc/...
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-1 votes
1 answer
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Are IPv4 more intuitively hard to track than IPv6?

I understand that it is easier for a human to intuitively figure out the alleged whereabouts of a machine if that machin's IP address is IPv6, rather than if its IPv4: For example, since I configured ...
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2 votes
0 answers
294 views

attach with gdb after dropping privileges

Under Ubuntu 16.04 LTS, I cannot seem to debug a once-privileged process for love or money as an unprivileged user. The file is setgid (mode 2755). It forks, and the child: releases its ...
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6 votes
1 answer
555 views

What are the security implications of capabilities in Kubernetes pods?

We have a Kubernetes deployment with an application that need to be on a VPN. We implement this requirement by running openvpn-client in a sidecar container within the pod with elevated capabilities: ...
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8 votes
2 answers
3k views

Difference between linux capabities and seccomp

I know seccomp (secure computing) is a way to restrict a process from making particular system calls. While linux capabilities provides a way to give privileges to specific user or process. So if I ...
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733 views

Why do capability-based security systems protect against the confused deputy problem?

According to Wikipedia (https://en.wikipedia.org/wiki/Confused_deputy_problem): In information security, the confused deputy problem is often cited as an example of why capability-based security ...
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15 votes
2 answers
7k views

Docker: when to use apparmor vs seccomp vs --cap-drop

Docker seems to support both apparmor and seccomp. Docker also allows to drop capabilities when running a container. However I couldn't find any documentation or guideline on when to use which ...
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1 vote
1 answer
794 views

Use of S/MIME capabilities attribute

If you examine an S/MIME-signed file with $ openssl cms -in file.sgn -noout -cmsout -print you see that S/MIME capabilities are also included in the signature: ... object: S/MIME Capabilities (1.2....
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4 votes
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9k views

Security implications of using SETCAP CAP_NET_RAW

In order to get around the 'problem' of applications requiring root privileges to run, I'm using: sudo setcap CAP_NET_ADMIN+ep "$(readlink -f /usr/sbin/app)" sudo setcap CAP_NET_RAW+ep "$(readlink -f ...
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  • 2,597
2 votes
2 answers
627 views

Making a file immutable (against kernel exploits)

I'd like to know how to make files completely immutable. "Completely" refers in this case to: immutable while the system is running. I could live with something like physical access where someone e.g ...
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4 votes
1 answer
556 views

Are Linux System Capabilities Considered Mandatory Access Controls?

DAC is not mandatory because access permissions are left up to the resource owner's discretion. Mandatory Access Control (Smack, SELinux, etc) administration can only be accomplished by a process/...
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2 votes
1 answer
871 views

What is the difference between claims and capabilities in access control?

I've read about the differences between capabilities and access control lists, but to me capabilities seem similar to claims. Can anyone explain the difference, if there is one?
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3 votes
2 answers
2k views

Do `sudo` and `su` belong to capability-based security?

In Linux, do sudo and su belong to Capability-based security ? For example, when editing a system file, we usually need sudo or su to temporarily switch to user root. Does this example belong to ...
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5 votes
1 answer
800 views

Capability-based security vs protection rings: in what sense are they diametrically opposite?

From https://en.wikipedia.org/wiki/Capability-based_security Capability-based security is to be contrasted with an approach that uses hierarchical protection domains. From https://en.wikipedia.org/...
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6 votes
2 answers
1k views

Combining capability-based access control with SAML

I have been looking into various research on identity, PKI and access control trying to boil it down to a simplified methodology for IAM (Identity & Access Management). One thing which pops up in ...
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6 votes
2 answers
3k views

What are the practical differences between SELinux targeted mode and a capability based OS?

I recently asked a question about the differences between capabilities and mandatory access controls. Among the answers I got the point was made that systems like SE Linux in targeted mode are not a ...
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9 votes
5 answers
3k views

What is the practical difference between MAC and Capabilities

Both Mandatory Access Controls and Capabilities allow for fine grained privileges to be assigned to applications irrespective or in place of privileges inherited by the running user. Is there any ...
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