1,088 research outputs found
Side-channel based intrusion detection for industrial control systems
Industrial Control Systems are under increased scrutiny. Their security is
historically sub-par, and although measures are being taken by the
manufacturers to remedy this, the large installed base of legacy systems cannot
easily be updated with state-of-the-art security measures. We propose a system
that uses electromagnetic side-channel measurements to detect behavioural
changes of the software running on industrial control systems. To demonstrate
the feasibility of this method, we show it is possible to profile and
distinguish between even small changes in programs on Siemens S7-317 PLCs,
using methods from cryptographic side-channel analysis.Comment: 12 pages, 7 figures. For associated code, see
https://polvanaubel.com/research/em-ics/code
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Efficient, portable template attacks
Template attacks recover data values processed by tamper-resistant
devices from side-channel waveforms, such as supply-current
fluctuations (power analysis) or electromagnetic emissions. They
first profile a device to generate multivariate statistics of the
waveforms emitted for each of a set of known processed values, which
then identify maximum-likelihood candidates of unknown processed
values during an attack. We identify several practical obstacles
arising in the implementation of template attacks, ranging from
numerical errors to the incompatibility of templates across
different devices, and propose and compare several solutions. We
identify pooled covariance matrices and prior dimensionality
reduction through Fisher's Linear Discriminant Analysis as
particularly efficient and effective, especially where many attack
traces can be acquired. We evaluate alternative algorithms not only
for the task of recovering key bytes from a hardware implementation
of the Advanced Encryption Standard; we even reconstruct the value
transferred by an individual byte-load instruction, with success
rates reaching 85% (or a guessing entropy of less than a quarter
bit remaining) after 1000 attack traces, thereby demonstrating
direct eavesdropping of 8-bit parallel data lines. Using different
devices during the profiling and attack phase can substantially
reduce the effectiveness of template attacks. We demonstrate that
the same problem can also occur across different measurement
campaigns with the same device and that DC offsets (e.g. due to
temperature drift) are a significant cause. We improve the
portability of template parameters across devices by manipulating
the DC content of the eigenvectors that form the projection matrix
used for dimensionality reduction of the waveforms
Similar operation template attack on RSA-CRT as a case study
A template attack, the most powerful side-channel attack methods, usually first builds the leakage profiles from a controlled profiling device, and then uses these profiles to recover the secret of the target device. It is based on the fact that the profiling device shares similar leakage characteristics with the target device. In this study, we focus on the similar operations in a single device and propose a new variant of the template attack, called the similar operation template attack (SOTA). SOTA builds the models on public variables (e.g., input/output) and recovers the values of the secret variables that leak similar to the public variables. SOTA’s advantage is that it can avoid the requirement of an additional profiling device. In this study, the proposed SOTA method is applied to a straightforward RSA-CRT implementation. Because the leakage is (almost) the same in similar operations, we reduce the security of RSA-CRT to a hidden multiplier problem (HMP) over GF(q), which can be solved byte-wise using our proposed heuristic algorithm. The effectiveness of our proposed method is verified as an entire prime recovery procedure in a practical leakage scenario
Attacking PUF-Based Pattern Matching Key Generators via Helper Data Manipulation
Abstract. Physically Unclonable Functions (PUFs) provide a unique signature for integrated circuits (ICs), similar to a fingerprint for humans. They are primarily used to generate secret keys, hereby exploiting the unique manufacturing variations of an IC. Unfortunately, PUF output bits are not perfectly reproducible and non-uniformly distributed. To obtain a high-quality key, one needs to implement additional post-processing logic on the same IC. Fuzzy extractors are the well-established standard solution. Pattern Matching Key Generators (PMKGs) have been proposed as an alternative. In this work, we demonstrate the latter construction to be vulnerable against manipulation of its public helper data. Full key recovery is possible, although depending on system design choices. We demonstrate our attacks using a 4-XOR arbiter PUF, manufactured in 65nm CMOS technology. We also propose a simple but effective countermeasure
Side-Channel Expectation-Maximization Attacks
Block ciphers are protected against side-channel attacks by masking. On one hand, when the leakage model is unknown, second-order correlation attacks are typically used. On the other hand, when the leakage model can be profiled, template attacks are prescribed. But what if the profiled model does not exactly match that of the attacked device?
One solution consists in regressing on-the-fly the scaling parameters from the model. In this paper, we leverage an Expectation-Maximization (EM) algorithm to implement such an attack. The resulting unprofiled EM attack, termed U-EM, is shown to be both efficient (in terms of number of traces) and effective (computationally speaking). Based on synthetic and real traces, we introduce variants of our U-EM attack to optimize its performance, depending on trade-offs between model complexity and epistemic noise. We show that the approach is flexible, in that it can easily be adapted to refinements such as different points of interest and number of parameters in the leakage model
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