13,441 research outputs found
Spatiotemporal patterns and predictability of cyberattacks
A relatively unexplored issue in cybersecurity science and engineering is
whether there exist intrinsic patterns of cyberattacks. Conventional wisdom
favors absence of such patterns due to the overwhelming complexity of the
modern cyberspace. Surprisingly, through a detailed analysis of an extensive
data set that records the time-dependent frequencies of attacks over a
relatively wide range of consecutive IP addresses, we successfully uncover
intrinsic spatiotemporal patterns underlying cyberattacks, where the term
"spatio" refers to the IP address space. In particular, we focus on analyzing
{\em macroscopic} properties of the attack traffic flows and identify two main
patterns with distinct spatiotemporal characteristics: deterministic and
stochastic. Strikingly, there are very few sets of major attackers committing
almost all the attacks, since their attack "fingerprints" and target selection
scheme can be unequivocally identified according to the very limited number of
unique spatiotemporal characteristics, each of which only exists on a
consecutive IP region and differs significantly from the others. We utilize a
number of quantitative measures, including the flux-fluctuation law, the Markov
state transition probability matrix, and predictability measures, to
characterize the attack patterns in a comprehensive manner. A general finding
is that the attack patterns possess high degrees of predictability, potentially
paving the way to anticipating and, consequently, mitigating or even preventing
large-scale cyberattacks using macroscopic approaches
On the exactness of soft theorems
Soft behaviours of S-matrix for massless theories reflect the underlying
symmetry principle that enforces its masslessness. As an expansion in soft
momenta, sub-leading soft theorems can arise either due to (I) unique structure
of the fundamental vertex or (II) presence of enhanced broken-symmetries. While
the former is expected to be modified by infrared or ultraviolet divergences,
the latter should remain exact to all orders in perturbation theory. Using
current algebra, we clarify such distinction for spontaneously broken (super)
Poincar\'e and (super) conformal symmetry. We compute the UV divergences of
DBI, conformal DBI, and A-V theory to verify the exactness of type (II) soft
theorems, while type (I) are shown to be broken and the soft-modifying
higher-dimensional operators are identified. As further evidence for the
exactness of type (II) soft theorems, we consider the alpha' expansion of both
super and bosonic open strings amplitudes, and verify the validity of the
translation symmetry breaking soft-theorems up to O(alpha'^6). Thus the
massless S-matrix of string theory "knows" about the presence of D-branes.Comment: 35 pages. Additional mathematica note book with the UV-divergenece of
the 6-point amplitude in AV/KS theor
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