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Unmasking Cloud Identities: From Behavioral Clustering to Automated Detection
Unit 42 clusters behavior of 40,000+ AWS identities from 125 cloud environments to map functional roles and enable lightweight SQL-based detection.
Palo Alto Unit 42 built an unsupervised behavioral clustering model using UMAP and HDBSCAN on AWS CloudTrail logs to map cloud identities to functional roles such as administrators, backup services, security tooling and DevOps. The study analyzed over 40,000 identities across 125 cloud environments over two months. The researchers show that heuristics extracted from the clustering map can be implemented in standard SQL, enabling role classification at scale without running a continuous ML pipeline. The methodology extends to audit logs from other cloud providers, SaaS and Kubernetes.
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A Ranking Approach for Measuring Calibration
Researchers propose rankECE, a ranking-based calibration error measure with theoretical guarantees that outperforms binned ECE approximations.
The paper introduces rankECE, an alternative to Expected Calibration Error (ECE) that measures miscalibration by comparing points with neighboring predicted-probability values. It addresses the impossibility of estimating ECE with guaranteed accuracy in assumption-free settings. Theoretical guarantees and empirical results establish rankECE as a better proxy for ECE than the binned approximations most commonly used in practice.
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Differential Privacy Meets Fixed Parameter Tractability: Algorithms and Lower Bounds
Theory paper combines differential privacy with fixed-parameter tractable encoders, improving approximation guarantees for combinatorial optimization and proving new lower bounds.
The paper studies combinatorial optimization under epsilon-differential privacy within the implicit encoder-decoder framework of Gupta et al. (SODA 2010), generalizing it to allow fixed-parameter tractable encoders. This circumvents approximation barriers inherent to polynomial-time algorithms and yields improved guarantees for fundamental combinatorial optimization problems. The authors establish the first representation-independent lower bounds: assuming a non-uniform variant of the Gap Exponential Time Hypothesis, no epsilon-DP encoder-decoder pair can achieve certain approximation guarantees with a subexponential-time decoder for sufficiently small epsilon. Representation-dependent lower bounds are also provided for larger epsilon.
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Security Incident – BGP Hijacking
Attackers BGP-hijacked Softaculous' Hetzner IP block for 33 hours, obtained valid TLS certificates, and delivered a malicious Virtualizor update to some servers.
Between August 28 and 30, 2026, AS62390 (NexonHost) announced 162.55.80.0/24 via transit AS6204 (Zet.net) without authorization, diverting traffic while retaining Hetzner's AS24940 on the AS path. The attacker obtained valid Let's Encrypt certificates for virtualizor.com domains because the CA's domain validation was also routed through the hijack, so affected connections showed no TLS warnings. A malicious Virtualizor update package reached a handful of installations; routing was fully restored, and reconstruction from RIPE RIS data showed all 368 collector peers carried the hijacked route at some point with roughly 28% time-weighted diversion.
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Revolut Data Leak May Trace Back to Compromised Italian Government Accounts
Attackers using a compromised Italian government PEC account impersonated law enforcement to obtain data on ~680 Revolut customers.
Revolut confirmed its systems were not breached; fraudulent data requests came from a compromised PEC mailbox tied to the Prefecture of Reggio Calabria on the pec.interno.it domain. Per the Financial Times, roughly 680 customers had identity documents, addresses, banking information, verification selfies and cryptocurrency transaction histories exposed. Researcher Korra of Duel described a 'spray and pray' operation using hundreds of crypto transaction IDs and fraudulent European Investigation Orders. Threat actor IAmNotAVillain claims six months of access and 147 GB exfiltrated from Italian law-enforcement systems, though this remains unverified.
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