  The vast accessibility of Synthetic Aperture Radar (SAR) images through
online portals has propelled the research across various fields. This
widespread use and easy availability have unfortunately made SAR data
susceptible to malicious alterations, such as local editing applied to the
images for inserting or covering the presence of sensitive targets.
Vulnerability is further emphasized by the fact that most SAR products, despite
their original complex nature, are often released as amplitude-only
information, allowing even inexperienced attackers to edit and easily alter the
pixel content. To contrast malicious manipulations, in the last years the
forensic community has begun to dig into the SAR manipulation issue, proposing
detectors that effectively localize the tampering traces in amplitude images.
Nonetheless, in this paper we demonstrate that an expert practitioner can
exploit the complex nature of SAR data to obscure any signs of manipulation
within a locally altered amplitude image. We refer to this approach as a
counter-forensic attack. To achieve the concealment of manipulation traces, the
attacker can simulate a re-acquisition of the manipulated scene by the SAR
system that initially generated the pristine image. In doing so, the attacker
can obscure any evidence of manipulation, making it appear as if the image was
legitimately produced by the system. We assess the effectiveness of the
proposed counter-forensic approach across diverse scenarios, examining various
manipulation operations. The obtained results indicate that our devised attack
successfully eliminates traces of manipulation, deceiving even the most
advanced forensic detectors.
