Asterisk vmail.cgi vulnerability
Assurance.com.au - Vulnerability Advisory
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Release Date:
07-Nov-2005
Software:
Asterisk Web-VoiceMail (Comedian VoiceMail)
http://www.asterisk.org/
Asterisk is a complete PBX in software. It runs on Linux, BSD and MacOSX and
provides all of the features you would expect from a PBX and more.
Asterisk does voice over IP in many protocols, and can interoperate with almost
all standards-based telephony equipment using relatively inexpensive hardware.
Versions affected:
Asterisk Versions <= 1.0.9
Asterisk Beta Versions <= 1.2.0-beta1
Asterisk @ Home Versions <= 1.5
Asterisk @ Home Beta Versions <= 2.0 Beta 4
Vulnerability discovered:
A vulnerability in the voicemail retrieval system allows an authenticated
user to download any .wav/.WAV file from the system, including other
users voicemail messages.
Vulnerability impact:
Low - Insecure web-ui causes breach of privacy
Vulnerability information
vmail.cgi doesn't clean a parameter passed by the web user which is
later used to open a file and return a raw stream to the user.
This allows any authenticated user of the voicemail system to listen to
other peoples messages, or to open any file with the extension .wav/.WAV
on the system.
Example:
http://asterisk.example.org/cgi-bin/vmail.cgi?action=audio&; \
folder=../201/INBOX&mailbox=200&context=default&password=12345 \
&msgid=0001&format=wav
This will return /var/spool/asterisk/voicemail/default/201/INBOX/msg0001.wav
when logged in as the 'extension 200' user.
Solution:
Asterisk has released patches for the vulnerabilities.
Ensure you are running Asterisk versions > 1.0.9 / 1.2.0-beta1
Ensure you are running Asterisk @ Home versions > 1.5 / 2.0 beta 4
References:
Assurance.com.au advisory
http://www.assurance.com.au/advisories/200511-asterisk.txt
Asterisk advisory note
http://www.asterisk.org/changelog
Credit:
Adam Pointon of Assurance.com.au
http://www.assurance.com.au/
Disclosure timeline:
17-Oct-2005 - Discovered during a quick audit of the asterisk web ui
18-Oct-2005 - Email sent to support and the primary author
18-Oct-2005 - Immediate response received
31-Oct-2005 - Patched version committed to CVS
07-Nov-2005 - Advisory released
About us:
Assurance.com.au is a specialised information security consultancy.
Our mission is to help organisations identify and secure their information
assets. Our expertise concentrates in security architecture design,
managed security and professional services in security testing/review
and compliance.
Supporting this approach are professional and managed services in the
following areas:
* Compliance Services - Penetration testing, security reviews,
compliance and audit services
* Wireless and mobility solutions - design, installation and management
of IEEE 802.11a/b/g (WiFi), tele-mobility and other wireless solutions
* UNIX-like systems, network and security advice and consulting
Assurance.com.au also provides organisations with services to support
compliance to legislative, public and internal/private standards. While
primarily specialising in Australian & New Zealand standards efforts
Assurance.com.au also works with other international standards related
to information security
These include:
* ISO/IEC 17799:*, AS/NZS 17799:*, BS7799
* ISO 15408 (Common Criteria), ITSEC, TCSEC
* ISO 13569, ISO 11131
* ACSI33, AS2805, AS3806, AS4360, AS4539, AS8018, HB231:2001, NPP4 (privacy)
* Sarbanes-Oxley