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Why Johnny Can't Encrypt: A Usability Evaluation of PGP 5.0 (1999)

Seminal 1999 USENIX study finds most novice users cannot correctly sign and encrypt email with PGP 5.0 in 90 minutes.

Whitten and Tygar's USENIX Security Symposium paper evaluates whether cryptography novices can use PGP 5.0 effectively, using cognitive walkthrough analysis and a laboratory user test. The majority of test participants failed to successfully sign and encrypt a message within 90 minutes, despite PGP 5.0 having a well-regarded graphical interface. The authors argue that security requires usability standards beyond those of general consumer software and propose domain-specific UI design principles for security. The paper is a foundational reference in usable security research.

Lobsters · security · 7d agoResearch

Zombie Card Attack Can Revive Expired Visa Cards for Contactless Payments

UMass Amherst researchers demonstrate Zombie Card, an NFC relay attack that revives expired Visa contactless cards for in-store purchases without breaking cryptography.

Researchers at the University of Massachusetts Amherst presented the Zombie Card attack at USENIX Security 2026, showing that Visa's Kernel 3 does not cryptographically bind the Application Expiration Date (tag 5F24) the terminal reads with the Track 2 expiry seen by the issuer. By positioning an NFC man-in-the-middle relay, an attacker can rewrite the terminal-facing expiration date of an expired card and complete contactless purchases, provided the account remains open under the same PAN and the bank does not independently re-check expiry. Testing across five major US banks found three distinct policies; Visa Kernel 3 accepted the modified date, while Mastercard, American Express, and Discover kernels declined modified transactions. Findings were disclosed to Visa and affected banks in May 2025, no CVE has been assigned, and no exploitation has been reported.

The Hacker News · 27d agoResearch

Researchers find a loophole that lets expired credit cards make unauthorized payments

UMass Amherst researchers showed at USENIX Security 2026 that NFC relay attacks can rewrite unprotected expiration dates, letting expired Visa contactless cards keep making payments.

UMass Amherst researchers presented the Zombie Card attack at USENIX Security 2026, using two smartphones to relay and modify NFC payment data from expired Visa cards. The expiration date lies outside the card's digital signature coverage in Visa Kernel 3, and one major US bank accepted $1-$500 test purchases plus live $2.79 and $3.19 purchases with rewritten dates. Mastercard, American Express, and Discover rejected tampered dates; researchers notified Visa in May 2025 and no CVE or confirmed fix existed at publication.

Help Net Security · 27d agoResearch

Are Unreachable Nodes Truly Safe? Fully Eclipsing Monero's P2P Network!

Researchers present Nyx and Moros, the first eclipse attacks against Monero nodes behind NATs, requiring no inbound access and demonstrated on mainnet.

The paper presents the first eclipse attacks tailored to unreachable Monero nodes operating behind NATs, requiring no inbound access to the victim. The attacks poison the peerlists of reachable nodes, which relay contamination to unreachable nodes' whitelists, then exploit Monero's outbound connection refresh logic to evict benign neighbors and monopolize all outbound connections. Nyx achieves a complete, persistent eclipse of long-running unreachable nodes in large-scale SEED Emulator simulations, while Moros stealthily eclipses newly joined nodes during bootstrapping and was demonstrated on the Monero mainnet. Countermeasures are proposed.

arXiv cs.CR · 7d agoResearch

Your Shredded Visa Card May Still Work at the Checkout

UMass Amherst researchers demonstrated expired Visa contactless cards can complete real purchases via relay attacks exploiting Visa Kernel 3's unsigned expiry date handling.

University of Massachusetts Amherst researchers presented at USENIX Security 2026 that expired Visa contactless cards can be revived for real purchases through an NFC man-in-the-middle attack on Visa's Kernel 3. The attack alters the expiry date the terminal sees (tag 5F24) while leaving the Track 2 Equivalent Data (tag 57) sent to the issuing bank unchanged, and the card's cryptographic signature does not cover the expiry date. Two Android phones emulating card and terminal relayed transactions within Visa's 500-millisecond limit. Mastercard, American Express, and Discover kernels blocked the attack, while Visa Kernel 3 did not; researchers also modified the Consumer Device Cardholder Verification Method flag at five US banks, and attackers can also exploit Terminal Verification Results zero-filling. Visa was notified in May 2025 and December 2025; no CVE has been assigned.

Security Affairs · 26d agoResearch

Risky Bulletin: Academics find source code overlaps between Geedge and China's Great Firewall

Academics linked Chinese vendor Geedge Networks' Tiangou Secure Gateway source code to one of the Great Firewall's three traffic filtering capabilities.

US researchers presenting at USENIX Security reconstructed Geedge Networks' Tiangou Secure Gateway firmware from over 100,000 leaked files, including Git repositories with commit history, and matched its filtering behavior to sections of China's Great Firewall. They found only 1 of 3 characterized DNS injectors matched Geedge code, noted the system relies on memory-unsafe C components and copied third-party code, and said its bugs could aid future circumvention tools. Geedge also exports censorship tools to Kazakhstan, Ethiopia, Pakistan, and Myanmar. The newsletter additionally rounds up multiple breaches.

Risky Business News · 26d agoResearch2