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The Security of the Fortuna PRNG

Providing random numbers on computers can be very difficult. Back in 2003, Niels Ferguson and I designed Fortuna as a secure PRNG. Particularly important is how it collects entropy from various processes on the computer and mixes them all together.

While Fortuna is widely used, there hadn’t been any real analysis of the system. This has now changed. A new paper by Yevgeniy Dodis, Adi Shamir, Noah Stephens-Davidowitz, and Daniel Wichs provides some theoretical modeling for entropy collection and PRNG. They analyze Fortuna and find it good but not optimal, and then provide their own optimal system.

Excellent, and long-needed, research.

Posted on March 11, 2014 at 6:28 AMView Comments

FIREWALK: NSA Exploit of the Day

Today’s item from the NSA’s Tailored Access Operations (TAO) group implant catalog:

FIREWALK

(TS//SI//REL) FIREWALK is a bidirectional network implant, capable of passively collecting Gigabit Ethernet network traffic, and actively injecting Ethernet packets onto the same target network.

(TS//SI//REL) FIREWALK is a bi-directional 10/100/1000bT (Gigabit) Ethernet network implant residing within a dual stacked RJ45 / USB connector FIREWALK is capable of filtering and egressing network traffic over a custom RF link and injecting traffic as commanded; this allows a ethernet tunnel (VPN) to be created between target network and the ROC (or an intermediate redirector node such as DNT’s DANDERSPRITZ tool.) FIREWALK allows active exploitation of a target network with a firewall or air gap protection.

(TS//SI//REL) FIREWALK uses the HOWLERMONKEY transceiver for back-end communications. It can communicate with an LP or other compatible HOWLERMONKEY based ANT products to increase RF range through multiple hops.

Status: Prototype Available—August 2008

Unit Cost: 50 Units $537K

Page, with graphics, is here. General information about TAO and the catalog is here.

In the comments, feel free to discuss how the exploit works, how we might detect it, how it has probably been improved since the catalog entry in 2008, and so on.

Posted on March 10, 2014 at 2:33 PMView Comments

Computer Network Exploitation vs. Computer Network Attack

Back when we first started getting reports of the Chinese breaking into U.S. computer networks for espionage purposes, we described it in some very strong language. We called the Chinese actions cyberattacks. We sometimes even invoked the word cyberwar, and declared that a cyber-attack was an act of war.

When Edward Snowden revealed that the NSA has been doing exactly the same thing as the Chinese to computer networks around the world, we used much more moderate language to describe U.S. actions: words like espionage, or intelligence gathering, or spying. We stressed that it’s a peacetime activity, and that everyone does it.

The reality is somewhere in the middle, and the problem is that our intuitions are based on history.

Electronic espionage is different today than it was in the pre-Internet days of the Cold War. Eavesdropping isn’t passive anymore. It’s not the electronic equivalent of sitting close to someone and overhearing a conversation. It’s not passively monitoring a communications circuit. It’s more likely to involve actively breaking into an adversary’s computer network—be it Chinese, Brazilian, or Belgian—and installing malicious software designed to take over that network.

In other words, it’s hacking. Cyber-espionage is a form of cyber-attack. It’s an offensive action. It violates the sovereignty of another country, and we’re doing it with far too little consideration of its diplomatic and geopolitical costs.

The abbreviation-happy U.S. military has two related terms for what it does in cyberspace. CNE stands for “computer network exploitation.” That’s spying. CNA stands for “computer network attack.” That includes actions designed to destroy or otherwise incapacitate enemy networks. That’s—among other things—sabotage.

CNE and CNA are not solely in the purview of the U.S.; everyone does it. We know that other countries are building their offensive cyberwar capabilities. We have discovered sophisticated surveillance networks from other countries with names like GhostNet, Red October, The Mask. We don’t know who was behind them—these networks are very difficult to trace back to their source—but we suspect China, Russia, and Spain, respectively. We recently learned of a hacking tool called RCS that’s used by 21 governments: Azerbaijan, Colombia, Egypt, Ethiopia, Hungary, Italy, Kazakhstan, Korea, Malaysia, Mexico, Morocco, Nigeria, Oman, Panama, Poland, Saudi Arabia, Sudan, Thailand, Turkey, UAE, and Uzbekistan.

When the Chinese company Huawei tried to sell networking equipment to the U.S., the government considered that equipment a “national security threat,” rightly fearing that those switches were backdoored to allow the Chinese government both to eavesdrop and attack US networks. Now we know that the NSA is doing the exact same thing to Americanmade equipment sold in China, as well as to those very same Huawei switches.

The problem is that, from the point of view of the object of an attack, CNE and CNA look the same as each other, except for the end result. Today’s surveillance systems involve breaking into the computers and installing malware, just as cybercriminals do when they want your money. And just like Stuxnet: the U.S./Israeli cyberweapon that disabled the Natanz nuclear facility in Iran in 2010.

This is what Microsoft’s General Counsel Brad Smith meant when he said: “Indeed, government snooping potentially now constitutes an ‘advanced persistent threat,’ alongside sophisticated malware and cyber attacks.”

When the Chinese penetrate U.S. computer networks, which they do with alarming regularity, we don’t really know what they’re doing. Are they modifying our hardware and software to just eavesdrop, or are they leaving :logic bombs” that could be triggered to do real damage at some future time? It can be impossible to tell. As a 2011 EU cybersecurity policy document stated (page 7):

…technically speaking, CNA requires CNE to be effective. In other words, what may be preparations for cyberwarfare can well be cyberespionage initially or simply be disguised as such.

We can’t tell the intentions of the Chinese, and they can’t tell ours, either.

Much of the current debate in the U.S. is over what the NSA should be allowed to do, and whether limiting the NSA somehow empowers other governments. That’s the wrong debate. We don’t get to choose between a world where the NSA spies and one where the Chinese spy. Our choice is between a world where our information infrastructure is vulnerable to all attackers or secure for all users.

As long as cyber-espionage equals cyber-attack, we would be much safer if we focused the NSA’s efforts on securing the Internet from these attacks. True, we wouldn’t get the same level of access to information flows around the world. But we would be protecting the world’s information flows—including our own—from both eavesdropping and more damaging attacks. We would be protecting our information flows from governments, nonstate actors, and criminals. We would be making the world safer.

Offensive military operations in cyberspace, be they CNE or CNA, should be the purview of the military. In the U.S., that’s CyberCommand. Such operations should be recognized as offensive military actions, and should be approved at the highest levels of the executive branch, and be subject to the same international law standards that govern acts of war in the offline world.

If we’re going to attack another country’s electronic infrastructure, we should treat it like any other attack on a foreign country. It’s no longer just espionage, it’s a cyber-attack.

This essay previously appeared on TheAtlantic.com.

Posted on March 10, 2014 at 6:46 AMView Comments

COTTONMOUTH-III: NSA Exploit of the Day

Today’s item from the NSA’s Tailored Access Operations (TAO) group implant catalog:

COTTONMOUTH-III

(TS//SI//REL) COTTONMOUTH-III (CM-III) is a Universal Serial Bus (USB) hardware implant, which will provide a wireless bridge into a target network as well as the ability to load exploit software onto target PCs.

(TS//SI//REL) CM-III will provide air-gap bridging, software persistence capability, “in-field” re-programmability, and covert communications with a host software implant over the USB. The RF link will enable command and data infiltration and exfiltration. CM-III will also communicate with Data Network Technologies (DNT) software (STRAITBIZARRE) through a covert channel implemented on the USB, using this communication channel to pass commands and data between hardware and software implants. CM-III will be a GENIE-compliant implant based on CHIMNEYPOOL.

(TS//SI//REL) CM-III conceals digital components (TRINITY), USB 2.0 HS hub, switches, and HOWLERMONKEY (HM) RF Transceiver within a RJ45 Dual Stacked USB connector. CM-I has the ability to communicate to other CM devices over the RF link using an over-the-air protocol called SPECULATION. CM-III can provide a short range inter-chassis link to other CM devices or an intra-chassis RF link to a long haul relay subsystem.

Status: Availability—May 2009

Unit Cost: 50 units: $1,248K

Page, with graphics, is here. General information about TAO and the catalog is here.

In the comments, feel free to discuss how the exploit works, how we might detect it, how it has probably been improved since the catalog entry in 2008, and so on.

Posted on March 7, 2014 at 2:41 PMView Comments

Academic Paper Spam

There seems to be an epidemic of computer-generated nonsense academic papers.

Labbé does not know why the papers were submitted—or even if the authors were aware of them. Most of the conferences took place in China, and most of the fake papers have authors with Chinese affiliations. Labbé has emailed editors and authors named in many of the papers and related conferences but received scant replies; one editor said that he did not work as a program chair at a particular conference, even though he was named as doing so, and another author claimed his paper was submitted on purpose to test out a conference, but did not respond on follow-up. Nature has not heard anything from a few enquiries.

In this arms race between fake-paper-generator and fake-paper-detector, the advantage goes to the detector.

Posted on March 7, 2014 at 6:13 AMView Comments

COTTONMOUTH-II: NSA Exploit of the Day

Today’s item from the NSA’s Tailored Access Operations (TAO) group implant catalog:

COTTONMOUTH-II

(TS//SI//REL) COTTONMOUTH-II (CM-II) is a Universal Serial Bus (USB) hardware Host Tap, which will provide a covert link over USB link into a target network. CM-II is intended to be operate with a long haul relay subsystem, which is co-located within the target equipment. Further integration is needed to turn this capability into a deployable system.

(TS//SI//REL) CM-II will provide software persistence capability, “in-field” re-programmability, and covert communications with a host software implant over the USB. CM-II will also communicate with Data Network Technologies (DNT) software (STRAITBIZARRE) through a covert channel implemented on the USB, using this communication channel to pass commands and data between hardware and software implants. CM-II will be a GENIE-compliant implant based on CHIMNEYPOOL.

(TS//SI//REL) CM-II consists of the CM-I digital hardware and the long haul relay concealed somewhere within the target chassis. A USB 2.0 HS hub with switches is concealed in a dual stacked USB connector, and the two parts are hard-wired, providing a intra-chassis link. The long haul relay provides the wireless bridge into the target’s network.

Unit Cost: 50 units: $200K

Status: Availability—September 2008

Status: Availability—January 2009

Unit Cost: 50 units: $1,015K

Page, with graphics, is here. General information about TAO and the catalog is here.

In the comments, feel free to discuss how the exploit works, how we might detect it, how it has probably been improved since the catalog entry in 2008, and so on.

Posted on March 6, 2014 at 2:18 PMView Comments

Wi-Fi Virus

Researchers have demonstrated the first airborne Wi-Fi computer virus. The paper, by Jonny Milliken, Valerio Selis, and Alan Marshall, is “Detection and analysis of the Chameleon WiFi access point virus,” EURASIP Journal on Information Security.

Abstract: This paper analyses and proposes a novel detection strategy for the ‘Chameleon’ WiFi AP-AP virus. Previous research has considered virus construction, likely virus behaviour and propagation methods. The research here describes development of an objective measure of virus success, the impact of product susceptibility, the acceleration of infection and the growth of the physical area covered by the virus. An important conclusion of this investigation is that the connectivity between devices in the victim population is a more significant influence on virus propagation than any other factor. The work then proposes and experimentally verifies the application of a detection method for the virus. This method utilises layer 2 management frame information which can detect the attack while maintaining user privacy and user confidentiality, a key requirement in many security solutions.

Posted on March 6, 2014 at 5:44 AMView Comments

COTTONMOUTH-I: NSA Exploit of the Day

Today’s item from the NSA’s Tailored Access Operations (TAO) group implant catalog:

COTTONMOUTH-I

(TS//SI//REL) COTTONMOUTH-I (CM-I) is a Universal Serial Bus (USB) hardware implant which will provide a wireless bridge into a target network as well as the ability to load exploit software onto target PCs.

(TS//SI//REL) CM-I will provide air-gap bridging, software persistence capability, “in-field” re-programmability, and covert communications with a host software implant over the USB. The RF link will enable command and data infiltration and exfiltration. CM-I will also communicate with Data Network Technologies (DNT) software (STRAITBIZARRE) through a covert channel implemented on the USB, using this communication channel to pass commands and data between hardware and software implants. CM-I will be a GENIE-compliant implant based on CHIMNEYPOOL.

(TS//SI//REL) CM-I conceals digital components (TRINITY), USB 1.1 FS hub, switches, and HOWLERMONKEY (HM) RF Transceiver within the USB Series-A cable connector. MOCCASIN is the version permanently connected to a USB keyboard. Another version can be made with an unmodified USB connector at the other end. CM-I has the ability to communicate to other CM devices over the RF link using an over-the-air protocol called SPECULATION.

Status: Availability—January 2009

Unit Cost: 50 units: $1,015K

Page, with graphics, is here. General information about TAO and the catalog is here.

In the comments, feel free to discuss how the exploit works, how we might detect it, how it has probably been improved since the catalog entry in 2008, and so on.

Posted on March 5, 2014 at 2:27 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.