Affected Products: Mitel 6869i Voip Deskphone Version 4.2.2032 - SIP
Not Affected: unknown
Vulnerability: Mitel 6869i SIP Deskphone 4.2.2032: Unauthenticated Bash
Command Injection Vulnerability with Root Priviledges in
2019/08/08 BlueBox Security releases this advisory
The Mitel 6869i is a desktop VoIP phone offering telephony features.
A webservice running on the TCP Port 49249 is used to administrate the phone's
VoIP settings, upgrade the firmware and change security settings.
The Webserver on port 49249 of the Mitel 6869i phone is using the "webuploadconfig" cgi-script,
an arm linux elf executable file, to upload ring tone audio files to the
phone with the page=upload_ringtone parameter.
The execution of this cgi-script does not require prior authentication.
Futhermore the script is vulnerable to Bash Command Injection.
The filename value of the POST request is used unsanitized in a system() call.
The vulnerable POST request to the webuploadconfig-script is the following:
POST //cgi-bin/webuploadconfig?page=upload_ringtone&action=submit§ion=0&conn=1 HTTP/1.1
Content-Type: multipart/form-data; boundary=------------------------2754e6a90f270263
Content-Disposition: form-data; name="file"; filename="`ping -c 1 192.168.178.140`"
By inserting "|command", "`command`" or "$(command) as the value of the "filename" parameter
the "command" is executed on the underlying linux operating system.
The following linux bash commandline exploits this vulnerability and executes the
command "ping -c 1 192.168.178.140" on the Mitel 6869i phone with the IP Adress
192.168.178.147 with root priviledges:
$ echo "pwned" | curl -F "file=@-;filename=\`ping -c 1 192.168.178.140\`" \
To verify the successfull completion of the ping-command on the Mitel 6869i
phone, start tcpdump on the host system and listen for incoming icmp requests.
(eg by running tcpdump -i eth0 -n icmp)
The "webuploadconfig" cgi-script also runs with superuser root-priviledges as
the telnetd service can be started on the restricted TCP-port 23 by replacing
the ping-command with "telnetd &".
The described problems allow an unauthenticated attacker to run arbitary linux
operating system commands with root-priledges. This leads to a complete comprimise
of the Mitel 6869i phone and therefore also the possibility to eavesdrop on the
We recommend to properly perform input parsing of the filename parameter to avoid
Command Injection vulnerabilities.
As a quick fix blocking access to the port 49249 is advisable.
Bug found by Axel Rengstorf <firstname.lastname@example.org> of Bluebox Security
This Advisory and Upcoming Advisories:
About BlueBox Security:
BlueBox Security is a vendor-independent security consulting company
specialising in the areas of voip/pbx telephone infrastructures security
analysis, source code audits and analysis of iot/embedded systems.
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