UMass Amherst researchers showed expired Visa contactless cards can make real purchases by exploiting an unsigned expiry field in Visa’s EMV kernel. Researchers at the University of Massachusetts Amherst demonstrated at USENIX Security 2026 in Baltimore that expired Visa contactless credit cards can complete real purchases, including transactions at live retail and grocery merchants, by exploiting a gap in how the payment protocol handles expiration dates. The paper is titled “Zombie Cards Back Online: Reviving Expired Credit Cards for Contactless Payments,” and the name is accurate. Raja Hasnain Anwar, Gerard DeCunha, and Muhammad Taqi Raza built the attack around a structural weakness in EMV, the contactless payment protocol used by Visa, Mastercard, American Express, and Discover. “A central source of fragility is that the EMV contactless protocol is a selectively authenticated transaction flow. Many data objects are exchanged in plaintext between the card and terminal [2], and only a subset is later bound to cryptographic verification via Offline Data Authentication (ODA) and issuer-verified cryptograms.” reads the paper. “In consequence, an adversary who obtains a man-in-the-middle position on the NFC channel can tamper with decision-critical fields that are consumed by the terminal but are not end-to-end integrity protected. Prior NFC attacks [10–12, 44], including relay-based manin-the-middle techniques, exploit this gap by manipulating transaction-relevant objects in transit while leaving cryptographic checks intact.” The attack exploits a specific design decision in Visa’s Kernel 3, the software layer that implements the EMV protocol for Visa transactions. A Visa contactless transaction presents the expiration date twice: once in a field the payment terminal reads (tag 5F24, the Application Expiration Date) and once in a field the issuing bank reads (tag 57, Track 2 Equivalent Data). These two representations should be tied together by a cryptographic signature, but in Visa’s implementation they aren’t. The relay attack changes only the expiry date that the payment terminal sees, replacing it with a future date while leaving the data sent to the bank unchanged. The card’s digital signature remains valid because it does not cover the expiry date. As a result, the bank receives a transaction that appears legitimate and passes its normal security checks. In simple terms, an attacker can change the expiry date between the card and the terminal without breaking the card’s cryptographic protection. The relay itself is two NFC-capable Android phones running custom software over Wi-Fi: one emulates a card, one emulates a terminal. Each communication round trip added roughly 20 milliseconds for relay alone and about 50 milliseconds with the date modification, keeping the per-transaction average around 415 milliseconds, within Visa’s 500-millisecond command limit. None of the test hardware used EMV’s optional Relay Resistance Protocol, which would have detected the added latency by bounding permissible response times. Mastercard, American Express, and Discover all blocked the attack. Mastercard’s terminal checks consistency between the two expiry representations during record parsing and treats a mismatch as a card data error. American Express binds the expiration date into the data covered by offline authentication, so a modified value produces a hash mismatch. Discover’s kernel wraps the modified transaction objects into the verified transaction hash, and those also failed. Visa’s Kernel 3 does none of these things. The outcome also depended on the issuing bank. The researchers tested three banks with expired and replaced physical Visa cards and found three distinct policies, not a clean pass or fail split. Bank A accepted the modified transactions at $1.00, $100.00, and $500.00 in the lab, and completed purchases of $2.79 at a retail merchant and $3.19 at a grocery merchant on campus. Bank A also accepted transactions from both the expired original card and its replacement against the same account simultaneously, a separate finding that Anwar described as alarming. Bank B detected the modification but still accepted some transactions. A third bank tested on Discover’s kernel detected the edit and declined; however, it also showed the simultaneous-card problem without any modification at all. There is another finding that makes the issue more serious. Researchers changed the Consumer Device Cardholder Verification Method flag at five US banks, and the transactions worked at most of them. This flag controls how the terminal verifies the cardholder, and attackers can change it because the payment data can be modified while it travels between the card and the terminal. There is also another problem with Kernel 3. It sends the issuer a Terminal Verification Results value filled with zeros. This means the bank cannot tell whether the terminal checked the card’s expiry date or whether that check failed. The bank must therefore approve the transaction without seeing what the terminal actually detected. “Across all tests, the dominant factors that determine attack success or failure are: (i) the EMV kernel in use and whether expiry data fields are cryptographically bound to authenticated protocol outputs; (ii) issuer-side lifecycle enforcement, especially whether authorization is tied only to the active account and PAN or also to the specific card instrument and expiration date; and (iii) whether terminal-side validation results are visible to the issuer via TVR. In contrast, transaction amount1 , merchant category, and POS terminal brand did not independently determine the transaction outcome.” continues the paper. The researchers disclosed the findings to Visa in May 2025 and followed up in December 2025. The paper records that Visa acknowledged the report, said it passed initial triage, and indicated it was undergoing reproduction by Visa’s red team. No CVE has been assigned. Neither Visa nor any of the notified banks confirmed any mitigation as of the paper’s acceptance. The Register asked Visa for comment and received no response. The countermeasures the paper proposes sit at the kernel, terminal, and issuer layers: bind the expiry date cryptographically to an issuer-verifiable signature, require terminals to compare both expiry representations and make mismatches visible to the issuer, and have issuers authorize against the PAN-and-expiry combination rather than the PAN alone. For cardholders, the researchers recommend destroying the chip and magnetic stripe of expired cards rather than discarding them intact. Given that the attack requires only the expired physical card or sustained NFC proximity to it, that guidance is now slightly less hypothetical than it was before this paper. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, Visa)
A previously unknown malware family dubbed SynkLoader is being distributed in Microsoft Teams phishing campaigns to steal credentials via a fake lock screen. The attacker impersonates the target company's IT help desk, a tactic Microsoft highlighted earlier this year as increasingly common in multi-stage attacks. Expel’s security researcher Marcus Hutchins explains that the attacks direct the victim to install a fake “PowerShell Cleaner” executable (.MSI) hosted in Microsoft Azure, making the download appear trustworthy. Analysis of the malware showed "compile dates and file timestamps indicating it was first compiled and distributed around July 28, 2026." The installer extracts a PowerShell script named cleaner.ps1 and a ZIP archive containing the Python framework, a malicious Python script, precompiled Python libraries, and several fake Microsoft runtime DLLs.
Using the same email, phone number, payment method, and other identifiers makes it easier for data brokers and attackers to profile your activity. Anonyome Labs explains how separate digital personas can reduce correlation and limit the impact of breaches, spam, and identity theft.
Microsoft has patched a maximum-severity vulnerability in the Entra ID identity and access management (IAM) platform that has been exploited in attacks.
GitLab flaw CVE-2026-19478 is now under active exploitation, allowing unauthenticated attackers to modify or delete public projects. WatchTowr researchers warn of active exploitation of critical GitLab flaw CVE-2026-19478 (CVSS score of 9.4). This week, GitLab pushed out an emergency patch to address this flaw, which could let an attacker with zero credentials remotely modify or delete public projects and user data. “GitLab has remediated an issue that under certain conditions could allow an unauthenticated user to remotely modify or delete public projects and user data via a GraphQL directive.” reads the advisory. GitLab issued an emergency patch on August 17, five days after its regular update. The vulnerability impacts only self-managed installations, users should upgrade to versions 19.2.4, 19.1.6, 19.0.8, and 18.11.11. There’s a gap worth flagging for anyone still sitting on an older release. The available patches don’t cover the 18.2 through 18.10 branches, even though those versions technically fall inside the affected range. If you’re running anything in that window, staying put isn’t really an option; you’ll need to upgrade to a patched branch entirely rather than waiting for a fix that isn’t coming for your current one. hiimguardian reported the flaw through the company HackerOne bug bounty program. Organizations should urgently patch internet-facing GitLab servers. Until they can update, they should restrict unauthenticated access to /api/graphql, disable public repositories where possible, and check logs for requests containing @gl_introduced. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, CVE-2026-19478)
Cl0p claims over 40 organizations fell victim to attacks exploiting a PTC Windchill and FlexPLM vulnerability. Cl0p is using a familiar strategy again: exploit one flaw in enterprise software to attack many companies, then publish the victims’ names if they refuse to pay. The group claims it has targeted more than 40 organizations through a vulnerability in PTC’s Windchill and FlexPLM platforms, which manufacturers and engineering companies use to manage product and design data. CVE-2026-12569 (CVSS score of 9.3) is a critical remote code execution (RCE) vulnerability in PTC Windchill PDMlink and PTC FlexPLM. An attacker can exploit this vulnerability through the deserialization of untrusted data. The flaw impacts all CPS versions and Windchill and FlexPLM releases prior to 11.0 M030. In June, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the flaw to its Known Exploited Vulnerabilities (KEV) catalog. German police reportedly warned organizations directly that attacks were coming, which tells you the exploitation window here wasn’t exactly subtle to security researchers watching it unfold. Cl0p group’s tooling for this campaign goes well beyond a basic web shell. Security firm ReliaQuest found the group deployed a custom implant built for full data theft on its own, no additional tools required to actually pull data out once inside. A class loader like that turns a single web shell into an open-ended backdoor, useful for lateral movement, ransomware deployment, or just quietly sitting there for months. “ReliaQuest identified the web shell as a fully equipped extortion platform: it maps sensitive vault data, decrypts every credential in the Windchill keystore, and includes a custom Java class loader that lets Clop execute any additional code inside the application process, extending the shell into an unlimited backdoor for follow-on activity such as lateral movement, ransomware, or persistence.” reads the report published by ReliaQuest. “The web shell gives attackers a direct path to credential theft and large-scale data exfiltration, with no additional tooling required. Unlike generic command shells, this implant decrypts credentials, delivers malware, and maps stored files for exfiltration.” Cl0p’s naming strategy followed its usual slow build. The group initially posted partial company names on its leak site, then switched to full names starting August 12, and the victim count has climbed steadily since. For each organization, the listing includes what type of data got stolen and roughly how much, ranging anywhere from a single gigabyte up to multiple terabytes depending on the target. The stolen data includes databases, project files, backups, engineering documents, blueprints, diagrams and corporate files, as well as images. The victim list reads like a cross-section of major manufacturing and industrial names: Shell, Philips, Fiserv, Zebra Technologies, Ingersoll Rand, Toast, Mindray, and Largan Precision, the company that supplies camera lenses for Apple’s devices. Researchers noticed that GE was on the list briefly before quietly disappearing from Cl0p’s site, a move that usually signals either a ransom payment or at least resumed negotiations behind closed doors. Shell, Philips, Fiserv, and GE have all publicly acknowledged awareness of the claims and said they’re investigating, though none has confirmed a significant breach so far. None of this is a new pattern for Cl0p specifically; it’s the same mass-exploitation-then-extortion model the group has run repeatedly against Oracle E-Business Suite, MOVEit, Cleo, and GoAnywhere over the past few years. What’s different this time is the target: enterprise PLM software sits deep inside manufacturing supply chains, holding the exact kind of engineering data that competitors and nation-states alike would pay real money to see. If your organization runs Windchill or FlexPLM and hasn’t checked for this specific CVE yet, that’s the item to move to the top of today’s list. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, Cl0p )
Microsoft on Thursday warned of a maximum-severity security flaw in Entra ID that it said has been exploited in the wild, but noted that no customer action is required. The vulnerability, tracked as CVE-2026-69836 (CVSS score: 10.0), is a case of remote code execution impacting the tech giant's cloud-based identity and access management service. It was previously called Azure Active Directory
AI is making phishing attacks more personalized, convincing, and difficult for traditional email filters to detect. Kaseya explains how MSPs can monitor identity, email, and endpoint activity to detect and contain attacks that make it past the inbox.
The Cybersecurity and Infrastructure Security Agency (CISA) warned federal agencies that threat actors are now exploiting a critical MLflow vulnerability. MLflow is an open-source AI engineering platform for large language models (LLMs) and agents backed by the Linux Foundation, with over 30 million monthly downloads, used by thousands of organizations to debug, evaluate, optimize, and monitor AI applications. Tracked as CVE-2026-64849, this critical DNS-rebinding server-side request forgery (SSRF) bypass in MLflow's outbound webhook delivery was patched in version 3.15.0 and can be used by attackers without privileges to remotely access internal services or cloud metadata configurations on unpatched instances. "The default MLflow Tracking Server (mlflow server, no authentication, default SQLite backend) exposes the model-registry webhooks API unauthenticated, including a synchronous POST /api/2.0/mlflow/webhooks/{id}/test endpoint that returns the upstream response status and body to the caller," MLflow's security team says in a security advisory issued three weeks ago.
Unit 42 details how attackers exploit enterprise collaboration tools for identity phishing and credential theft. Discover key defense strategies. The post Identity Abuse Through Trusted Communication Channels appeared first on Unit 42.
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