  Machine-learning methods have already been exploited as useful tools for
detecting malicious executable files. They leverage data retrieved from malware
samples, such as header fields, instruction sequences, or even raw bytes, to
learn models that discriminate between benign and malicious software. However,
it has also been shown that machine learning and deep neural networks can be
fooled by evasion attacks (also referred to as adversarial examples), i.e.,
small changes to the input data that cause misclassification at test time. In
this work, we investigate the vulnerability of malware detection methods that
use deep networks to learn from raw bytes. We propose a gradient-based attack
that is capable of evading a recently-proposed deep network suited to this
purpose by only changing few specific bytes at the end of each malware sample,
while preserving its intrusive functionality. Promising results show that our
adversarial malware binaries evade the targeted network with high probability,
even though less than 1% of their bytes are modified.
