0x22bb
/
hacktricks
mirror of https://github.com/carlospolop/hacktricks.git
1
2
Fork 0
Code Releases Activity

GITBOOK-3860: change request with no subject merged in GitBook

This commit is contained in:
CPol 2023-04-05 06:54:17 +00:00 committed by gitbook-bot
parent 45fc3b60ae
commit a94b1d55da
No known key found for this signature in database
GPG Key ID: 07D2180C7B12D0FF
2 changed files with 35 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
linux-hardening/privilege-escalation/docker-breakout/docker-breakout-privilege-escalation/README.md
View File

@ -534,10 +534,6 @@ Get Access Today:
## CVEs
### Cgroups escape (**CVE-2022-0492)**
****
### Runc exploit (CVE-2019-5736)
In case you can execute `docker exec` as root (probably with sudo), you try to escalate privileges escaping from a container abusing CVE-2019-5736 (exploit [here](https://github.com/Frichetten/CVE-2019-5736-PoC/blob/master/main.go)). This technique will basically **overwrite** the _**/bin/sh**_ binary of the **host** **from a container**, so anyone executing docker exec may trigger the payload.

35
linux-hardening/privilege-escalation/docker-breakout/namespaces/user-namespace.md
View File

@ -131,6 +131,41 @@ ps -ef | grep bash # The user inside the host is still root, not nobody
root 27756 27755 0 21:11 pts/10 00:00:00 /bin/bash
```
### Recovering Capabilities
In the case of user namespaces, **when a new user namespace is created, the process that enters the namespace is granted a full set of capabilities within that namespace**. These capabilities allow the process to perform privileged operations such as **mounting** **filesystems**, creating devices, or changing ownership of files, but **only within the context of its user namespace**.
For example, when you have the `CAP_SYS_ADMIN` capability within a user namespace, you can perform operations that typically require this capability, like mounting filesystems, but only within the context of your user namespace. Any operations you perform with this capability won't affect the host system or other namespaces.
{% hint style="warning" %}
Therefore, even if getting a new process inside a new User namespace **will give you all the capabilities back** (CapEff: 000001ffffffffff), you actually can **only use the ones related to the namespace** (mount for example) but not every one. So, this on its own is not enough to escape from a Docker container.
{% endhint %}
```bash
# There are the syscalls that are filtered after changing User namespace with:
unshare -UmCpf bash
Probando: 0x067 . . . Error
Probando: 0x070 . . . Error
Probando: 0x074 . . . Error
Probando: 0x09b . . . Error
Probando: 0x0a3 . . . Error
Probando: 0x0a4 . . . Error
Probando: 0x0a7 . . . Error
Probando: 0x0a8 . . . Error
Probando: 0x0aa . . . Error
Probando: 0x0ab . . . Error
Probando: 0x0af . . . Error
Probando: 0x0b0 . . . Error
Probando: 0x0f6 . . . Error
Probando: 0x12c . . . Error
Probando: 0x130 . . . Error
Probando: 0x139 . . . Error
Probando: 0x140 . . . Error
Probando: 0x141 . . . Error
Probando: 0x143 . . . Error
```
<details>
<summary><strong>HackTricks in</strong> <a href="https://twitter.com/carlospolopm"><strong>🐦 Twitter 🐦</strong></a> - <a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ Twitch</strong></a> <strong>Wed - 18.30(UTC) 🎙️</strong> - <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>