Category Archives: VoIP Security

Microsoft Researching Skype Password Reset Security Hole

This morning The Next Web reported on an exploit where Skype’s password reset web page could be used to hijack a user’s Skype account using only the password associated with the account. So… if you could guess someone’s email address (which can often be found through a Google search), you could effectively take over their Skype account.

Microsoft/Skype has DISABLED this feature while they investigate further so it appears that for the moment the security risk is limited.

However, it may be wise to watch closely the email account associated with your Skype ID for the next bit to see if any random password reset messages are sent to your account. Odds are that attackers will be sniffing around trying to see if there is any other way to exploit the apparent vulnerability.

The Next Web team reports that they were able to reproduce the attack on two Skype accounts of willing victims, confirming that the vulnerability was indeed real. They also reported the issue to Skype and worked with folks there.

The vulnerability is interesting in that it shows the complexity of modern communication applications. Skype is for the most part a desktop/mobile application, but yet it does rely on a centralized cloud-based service for authentication/passwords, etc. A vulnerability in the web interface for that central service then weakens the security of the overall system.

The “good” news for Microsoft/Skype is that because this appears to be a vulnerability in the web interface of the centralized system, this is probably something relatively easy for them to fix – and without requiring any client updates.

Kudos to Microsoft/Skype for reacting quickly to minimize the risk and we look forward to the issue being addressed.

UPDATE #1: Skype has issued a brief statement on their “heartbeat” web site with the same text that has been quoted in several articles.

UPDATE #2: The Verge has an article out now where many people in the comments are suggesting you change the email address associated with your Skype account to something less likely to be guessed. While Microsoft seems to have removed the immediate attack vector and this change is no longer critical to do, it may be something some of you may want to consider.

UPDATE #3: There’s a long Hacker News thread on this issue that also includes a link to an article walking through the exploit step-by-step as well as walking through links to protect your account. Note that because of the steps Microsoft has taken the exploit steps no longer work.

Digium Releases 3 Asterisk Security Advisories

Asterisk logoThis week Digium released three security advisories allowing remote authenticated sessions to either crash an Asterisk server or escalate user privileges.  The advisories are:

In all cases the solution is to upgrade to the latest releases of Asterisk Open Source (1.6.2.24, 1.8.11.1 or  10.3.1 ) or Asterisk Business Edition (C.3.7.4).

 

Free Webinar Tomorrow: Securing VoIP and Unified Communications Systems

USTelecomWant to join in to a free webinar/webcast to learn about VoIP and Unified Communications security? Tomorrow, Thursday, January 26, 2012, I (Dan York) will be speaking as part of US Telecom’s monthly educational webinar series on the topic of: “Securing VoIP and Unified Communications Systems“

The session will be at 1:00pm US Eastern. Registration is free using the “Register Now” link on the right side of the US Telecom webinar page. I’ll be spending about 30 minutes covering the range of security issues with VoIP and UC and then will have plenty of time for questions.

The abstract of the session includes:

What are the major security threats to today’s telecommunications infrastructure?

As telecom has evolved from the traditional circuit-switched PSTN to a new world of Voice-over-IP (VoIP) and Unified Communications (UC), what are the security implications? As services move to be based on the Session Initiation Protocol (SIP), how does that change the security of the system? Is this new IP-based world less or more secure? What are the threats and what are the best practices to protect against those threats?

I’ve always found these sessions to be quite enjoyable to do and have always enjoyed the dialogue that frequently happens with questions. I encourage you to register and participate.

If you can’t join live, US Telecom will be making an archive of the session available for 90 days. I believe it will be linked from the webinar page, but if not I will update this post with the information.

Asterisk Remote Crash Vulnerability in SIP Channel Driver

Asterisk

The folks over at the Digium security team today released security bulletin AST-2011-012 for a remote crash vulnerability in the SIP channel drive. For info about the attack, they state only:

A remote authenticated user can cause a crash with a malformed request due to an uninitialized variable.

An assumption from this statement would be that an UNauthenticated user could not carry out this attack… but I admit to not personally knowing the SIP channel driver of Asterisk enough to be able to stand behind this conclusion.

Regardless, updates have been released in the form of new versions 1.8.7.1 and 10.0.0-rc1.

Avaya Acquires UC Security Firm and SBC Vendor Sipera Systems

Fascinating news today that Avaya has acquired Sipera Systems for an undisclosed sum. We’ve covered Sipera here on this blog any number of times over the past years as they have been one of the few firms very specifically focused on “VoIP security”, or, to be more appropriately buzzword-compliant in 2011, “Unified Communications security.” In fact, the first video podcast I did for the Blue Box Podcast (when I was doing that) way back in August 2007 was with Sipera.

Over the years Sipera has hired some truly excellent people in the field, released some useful tools, originated great research and done a great bit in general to help keep the dialog going on publicly about VoIP/UC security.

The Avaya purchase is fascinating because, as Eric Krapf noted in a NoJitter post this morning, Avaya has been OEMing a Session Border Controller (SBC) solution from market leader Acme Packet for quite some time. As Eric notes:

The deal therefore could represent a shift in the enterprise SBC market, at a moment when E-SBCs are emerging as a key component of enterprise real-time communications deployments, especially in SIP trunking deployments. Acme Packet has been far and away the market share leader in SBCs, with over 50%, and its SBC works with all the leading enterprise communications platforms.

However, enterprise vendors including Cisco and Siemens (and now, it seems, Avaya) have released their own SBCs, and in the case of Siemens, the SBC only talks to Siemens platforms on the enterprise side of the device. It remains to be seen whether the Sipera SBC will work only with Avaya Aura–but it seems unlikely that anyone other than an Avaya customer would buy an Avaya SBC.

Now, the news release of course plays up how Sipera’s solutions work with both Avaya and non-Avaya systems but to Eric’s point there may in the future be little incentive for non-Avaya customers to purchase a solution, given that there are other “independent” players out there in the SBC market like Acme Packet, Ingate Systems, Sonus Networks and others.

Regardless of how it all shakes out, it is an interesting move and one that bears watching.

Congrats to our friends at Sipera and Avaya on the acquisition, and we look forward to seeing how it evolves.

Calling All Vendors! Test Your SIP over TLS at SIPit 29 Oct 24-28 in Monaco

SIPitAre you a vendor of SIP software or hardware devices? If so, do you support SRTP or SIP over TLS? If you do – or are thinking about doing so – why don’t you join Olle Johansson for some interoperability testing at SIPit 29, October 24-28, in Monaco?

Olle raised just that suggestion today in the VOIPSEC mailing list and said that he will be there focused on testing VoIP security (and also IPv6). As he said:

Customers need at least first hop TLS and SRTP to work as expected. They also need interoperability between devices. To get interoperability, everyone needs to work with it. It just doesn’t happen by accident. SIPit has been organised twice a year for 15 years in order to get the amount of interoperability we have today in SIP.

If you develop SIP software or devices – register for SIPit now. If you are a customer and have seen issues in this area, remind your vendors to participate. The more we are, the more time we can spend on VoIP protocol security.

The SIPit test events are outstanding places to go and test your software or hardware. For the relatively small fee and your time and travel, you have access to an incredible test bed in the form of all the other vendors participating. Where else will you get to interact with designers and engineers from all the major vendors and not only test your software/hardware, but also re-test your equipment if you try some fixes while you are there.

You still have time to register for SIPit29 and join Olle and others in the security testing.

P.S. If you aren’t aware of the SIPit events, more info can be found on the main SIPit site. They are held twice a year in various locations. The summaries of past SIPit events give you a good flavor for the type of testing that goes on.

Skype for iOS/iPhone Vulnerable to Cross-Site-Scripting (XSS) Attack

News from the SUPEREVR security blog is that Skype for iOS is vulnerable to a cross-site scripting (XSS) attack that allows an attacker to send someone a message and, for instance, capture that user’s address book from their iPhone.

The author of the article posted a video that demonstrates the attack:

He further states in a tweet that he notified Skype of the vulnerability on August 24th:

In case anyone is wondering, I disclosed the vulnerability to Skype on 8/24. I was told an update would be released early this month.

Skype has issued a statement through their PR firm:

We are working hard to fix this reported issue in our next planned release which we hope to roll out imminently. In the meantime, we always recommend people exercise caution in only accepting friend requests from people they know and practice common sense Internet security as always.

Skype’s mitigation recommendation is a good one as the default privacy setting is typically that you can only receive chat messages from people on your Contact list. Therefore, the attacker would have to be someone who you have authorized and added to your contact list.

Meanwhile, hopefully Skype will be out with their update soon.

P.S. Hat tip to Tom Keating for writing about this exploit as that was where I first learned of it.

VoIP Fraudster Pleads Guilty to $4.4 Million USD Theft of Services from AT&T, Verizon, Others

FbiNews out of the U.S. Federal Bureau of Investigation (FBI) last week was that a New Jersey man pled guilty to charges that he and his co-conspirators stole over $4.4 million USD of VoIP services from a range of VoIP service providers including AT&T, Verizon and many others.

Reading through the FBI news release, the scam really has nothing to do with “VoIP security”, per se, and everything to do with “social engineering.” Essentially, the group managed to appear to be a legitimate business so that VoIP service providers would let them resell their services to businesses. They then resold that service and pocketed the money without ever paying the service providers.

From the news release, it seems to have been a rather extensive scam:

To make it appear as if the shell companies were legitimate VoIP wholesalers and to induce the victim providers to extend credit to the companies on favorable terms, Tonangi and his co-conspirators took several fraudulent steps, including establishing fake business addresses for the shell companies at prominent New York locations, including the Empire State Building.

The co-conspirators also used Internet-based answering services that purported to connect callers to the shell companies’ various departments, such as accounts receivable and marketing, but really connected to cell phones controlled by the co-conspirators.

Tonangi and his co-conspirators created shell company e-mail accounts in the names of non-existent employees for communicating with victim providers; websites that contained false information, such as the names of non-existent employees and the companies’ fabricated qualifications to serve as VoIP wholesalers; and aliases to negotiate the purchase of VoIP services.

They also fabricated year-end financial reports that bore the logo of a national accounting firm in order to give the appearance that the shell companies’ financial reports had been reviewed by that firm.

When the victim providers sold VoIP services to the shell companies on credit, Tonangi and his co-conspirators would “bust out” the account by causing the companies to use substantially more VoIP services than the companies had been approved to buy in such a short period of time. The co-conspirators would do this over weekends and holidays so that the providers would not notice.

When the invoices for the services came due, the co-conspirators would send fake wire transfer confirmations via e-mail or submit small payments to keep the victim providers from cutting off service.

If victim providers sued or threatened to sue the shell companies, Tonangi and his co-conspirators would respond in legal pleadings or letters that they prepared in the name of a non-existent attorney, Frank Soss. Tonangi and Bhambhani created and used a fraudulent United States passport in the name Frank Soss by downloading and altering a exemplar passport image and photograph from the Internet.

Given the degree of subterfuge undertaken by the group, I’m not at all surprised that they fooled numerous companies into extending credit for VoIP services. When you are doing due diligence on a new customer, you would explore many of the avenues that these folks seem to have covered.

It’s not clear from the news release or any other information I’ve seen online what if any VoIP technology was used here but given that the group was acting as a legitimate business they didn’t need anything very sophisticated. Many software and service options would have met their needs.

It’s good to see the FBI successfully cracking this fraud ring… sadly I’m sure there will be others as we see the increased usage of VoIP across the industry.

P.S. Thanks to J. Oquendo in the VOIPSEC mailing list for alerting us to this news from the FBI.

Voipscanner.com – a hosted service for scanning IP-PBXs

VoipscannerThis week at the SIPNOC event near DC, an attendee asked if I knew of any hosted services that would scan the external interface of a network to see if the VoIP services were secure. He sells SIP connectivity to small businesses, many of whom typically have purchased an IP-PBX from somewhere like a retail store and have minimal IT expertise. He wondered if there was a service he could refer these small businesses to so that they could check the security of their system. Basically something for VoIP along the lines of hosted services like “Shields Up” that will check the security of your firewall.

I didn’t know of such a service, but posted the question to the VOIPSEC mailing list. A couple of people contacted me privately about some services in the works, but then someone did pass along a link to a public service available now:

https://voipscanner.com/voipscanner/

Now, I’ve not used this service but I’m certainly aware of Sandro Gauci and a number of the different tools he has been working on, including SIPVicious and VOIPPACK. After watching his short video and seeing the sample report, this definitely looks like an interesting service.

Of course, with any hosted service my security paranoia is heightened and I want to know what will be done with my data. Will the scan of my IP-PBX be recorded on the Voipscanner.com servers? Will a copy of my report be saved there? Basically… can I trust the site? In looking through the terms of service after you click the graphic to “apply” for access I didn’t see any wording around this… but it’s also Friday and I’m tired… I could have missed it.

Anyway, this service is out there and for those of you comfortable with using such a service it may be useful for you. If you know of other similar services I’d also love to hear about them.

Speaking at SIPNOC on SIP Security – What Would You Like Me to Say To Service Providers?

Sipnoc2011 1Tomorrow I will be in Herndon, Virginia, outside of Washington, DC, at “SIPNOC: The SIP Network Operators Conference“. I will be speaking in two sessions (details here), one of which is a panel about “SIP Adoption and Network Security” and will include two other panelists from Acme Packet and Sipera Systems.

The panel discussion is planned to be about what are the primary security issues related to wider deployment of SIP at the network operator / service provider level, and what can we do about them. The discussion will be in a room full of people from various large operators / service providers.

I have my list of topics I intend to raise, but I’m curious about what you all might say… if you were to stand up in front of a room of network operators to talk about how they could improve the security of their SIP networks… or what the major issues are that you see… what would you say?

If you have thoughts, please do leave them as comments here. As I am on the panel representing VOIPSA, I’m certainly glad to incorporate comments from the wider community.

P.S. If you are at SIPNOC this week, please do say hello!