Linux has a sleeper agent working as a core developer

The latest news from Wikileaks, that GCHQ, the UK’s signal intelligence agency, has a sleeper agent working as a trusted member on the Linux kernel core development team should not come as a surprise to anybody.

The Linux kernel is embedded as a core component inside many critical systems; the kind of systems that intelligence agencies and other organizations would like full access.

The open nature of Linux kernel development makes it very difficult to surreptitiously introduce a hidden vulnerability. A friendly gatekeeper on the core developer team is needed.

In the Open source world, trust is built up through years of dedicated work. Funding the right developer to spend many years doing solid work on the Linux kernel is a worthwhile investment. Such a person eventually reaches a position where the updates they claim to have scrutinized are accepted into the codebase without a second look.

The need for the agent to maintain plausible deniability requires an arm’s length approach, and the GCHQ team made a wise choice in targeting device drivers as cost-effective propagators of hidden weaknesses.

Writing a device driver requires the kinds of specific know-how that is not widely available. A device driver written by somebody new to the kernel world is not suspicious. The sleeper agent has deniability in that they did not write the code, they simply ‘failed’ to spot a well hidden vulnerability.

Lack of know-how means that the software for a new device is often created by cutting-and-pasting code from an existing driver for a similar chip set, i.e., once a vulnerability has been inserted it is likely to propagate.

Perhaps it’s my lack of knowledge of clandestine control of third-party computers, but the leak reveals the GCHQ team having an obsession with state machines controlled by pseudo random inputs.

With their background in code breaking I appreciate that GCHQ have lots of expertise to throw at doing clever things with pseudo random numbers (other than introducing subtle flaws in public key encryption).

What about the possibility of introducing non-random patterns in randomised storage layout algorithms (he says waving his clueless arms around)?

Which of the core developers is most likely to be the sleeper agent? His codename, Basil Brush, suggests somebody from the boomer generation, or perhaps reflects some personal characteristic; it might also be intended to distract.

What steps need to be taken to prevent more sleeper agents joining the Linux kernel development team?

Requiring developers to provide a record of their financial history (say, 10-years worth), before being accepted as a core developer, will rule out many capable people. Also, this approach does not filter out ideologically motivated developers.

The world may have to accept that intelligence agencies are the future of major funding for widely used Open source projects.

MI5 agent caught selling Huawei exploits on Russian hacker forums

An MI5 agent has been caught selling exploits in Huawei products, on an underground Russian hacker forum (a paper analyzing the operation of these forums; perhaps the researchers were hired as advisors). How did this news become public? A reporter heard Mr Wang Kit, a senior Huawei manager, complaining about not receiving a percentage of the exploit sale, to add to his quarterly sales report. A fair point, given that Huawei are funding a UK centre to search for vulnerabilities.

The ostensive purpose of the Huawei cyber security evaluation centre (funded by Huawei, but run by GCHQ; the UK’s signals intelligence agency), is to allay UK fears that Huawei have added back-doors to their products, that enable the Chinese government to listen in on customer communications.

If this cyber centre finds a vulnerability in a Huawei product, they may or may not tell Huawei about it. Obviously, if it’s an exploitable vulnerability, and they think that Huawei don’t know about it, they could pass the exploit along to the relevant UK government department.

If the centre decides to tell Huawei about the vulnerability, there are two good reasons to first try selling it, to shady characters of interest to the security services:

  • having an exploit to sell gives the person selling it credibility (of the shady technical kind), in ecosystems the security services are trying to penetrate,
  • it increases Huawei’s perception of the quality of the centre’s work; by increasing the number of exploits found by the centre, before they appear in the wild (the centre has to be careful not to sell too many exploits; assuming they manage to find more than a few). Being seen in the wild adds credibility to claims the centre makes about the importance of an exploit it discovered.

How might the centre go about calculating whether to hang onto an exploit, for UK government use, or to reveal it?

The centre’s staff could organized as two independent groups; if the same exploit is found by both groups, it is more likely to be found by other hackers, than an exploit found by just one group.

Perhaps GCHQ knows of other groups looking for Huawei exploits (e.g., the NSA in the US). Sharing information about exploits found, provides the information needed to more accurately estimate the likelihood of others discovering known exploits.

How might Huawei estimate the number of exploits MI5 are ‘selling’, before officially reporting them? Huawei probably have enough information to make a good estimate of the total number of exploits likely to exist in their products, but they also need to know the likelihood of discovering an exploit, per man-hour of effort. If Huawei have an internal team searching for exploits, they might have the data needed to estimate exploit discovery rate.

Another approach would be for Huawei to add a few exploits to the code, and then wait to see if they are used by GCHQ. In fact, if GCHQ accuse Huawei of adding a back-door to enable the Chinese government to spy on people, Huawei could claim that the code was added to check whether GCHQ was faithfully reporting all the exploits it found, and not keeping some for its own use.

The 2019 Huawei cyber security evaluation report

The UK’s Huawei cyber security evaluation centre oversight board has released it’s 2019 annual report.

The header and footer of every page contains the text “SECRET”, which I assume is its UK government security classification. It lends an air of mystique to what is otherwise a meandering management report.

Needless to say, the report contains the usually puffery, e.g., “HCSEC continues to have world-class security researchers…”. World class at what? I hear they have some really good mathematicians, but have serious problems attracting good software engineers (such people can be paid a lot more, and get to do more interesting work, in industry; the industry demand for mathematicians, outside of finance, is weak).

The most interesting sentence appears on page 11: “The general requirement is that all staff must have Developed Vetting (DV) security clearance, …”. Developed Vetting, is the most detailed and comprehensive form of security clearance in UK government (to quote Wikipedia).

Why do the centre’s staff have to have this level of security clearance?

The Huawei source code is not that secret (it can probably be found online, lurking in the dark corners of various security bulletin boards).

Is the real purpose of this cyber security evaluation centre, to find vulnerabilities in the source code of Huawei products, that GCHQ can then use to spy on people?

Or perhaps, this centre is used for training purposes, with staff moving on to work within GCHQ, after they have learned their trade on Huawei products?

The high level of security clearance applied to the centre’s work is the perfect smoke-screen.

The report claims to have found “Several hundred vulnerabilities and issues…”; a meaningless statement, e.g., this could mean one minor vulnerability and several hundred spelling mistakes. There is no comparison of the number of vulnerabilities found per effort invested, no comparison with previous years, no classification of the seriousness of the problems found, no mention of Huawei’s response (i.e., did Huawei agree that there was a problem).

How many vulnerabilities did the centre find that were reported by other people, e.g., the National Vulnerability Database? This information would give some indication of how good a job the centre was doing. Did this evaluation centre find the Huawei vulnerability recently disclosed by Microsoft? If not, why not? And if they did, why isn’t it in the 2019 report?

What about comparing the number of vulnerabilities found in Huawei products against the number found in vendors from the US, e.g., CISCO? Obviously back-doors placed in US products, at the behest of the NSA, need not be counted.

There is some technical material, starting on page 15. The configuration and component lifecycle management issues raised, sound like good points, from a cyber security perspective. From a commercial perspective, Huawei want to quickly respond to customer demand and a dynamic market; corners are likely to be cut off good practices every now and again. I don’t understand why the use of an unnamed real-time operating system was flagged: did some techie gripe slip through management review? What is a C preprocessor macro definition doing on page 29? This smacks of an attempt to gain some hacker street-cred.

Reading between the lines, I get the feeling that Huawei has been ignoring the centre’s recommendations for changes to their software development practices. If I were on the receiving end, I would probably ignore them too. People employed to do security evaluation are hired for their ability to find problems, not for their ability to make things that work; also, I imagine many are recent graduates, with little or no practical experience, who are just repeating what they remember from their course work.

Huawei should leverage its funding of a GCHQ spy training centre, to get some positive publicity from the UK government. Huawei wants people to feel confident that they are not being spied on, when they use Huawei products. If the government refuses to play ball, Huawei should shift its funding to a non-government, open evaluation center. Employees would not need any security clearance and would be free to give their opinions about the presence of vulnerabilities and ‘spying code’ in the source code of Huawei products.