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  • Microsoft Patch Tuesday, December 2025 Edition – Krebs on Security

    Microsoft Patch Tuesday, December 2025 Edition – Krebs on Security


    Microsoft today pushed updates to fix at least 56 security flaws in its Windows operating systems and supported software. This final Patch Tuesday of 2025 tackles one zero-day bug that is already being exploited, as well as two publicly disclosed vulnerabilities.

    Despite releasing a lower-than-normal number of security updates these past few months, Microsoft patched a whopping 1,129 vulnerabilities in 2025, an 11.9% increase from 2024. According to Satnam Narang at Tenable, this year marks the second consecutive year that Microsoft patched over one thousand vulnerabilities, and the third time it has done so since its inception.

    The zero-day flaw patched today is CVE-2025-62221, a privilege escalation vulnerability affecting Windows 10 and later editions. The weakness resides in a component called the “Windows Cloud Files Mini Filter Driver” — a system driver that enables cloud applications to access file system functionalities.

    “This is particularly concerning, as the mini filter is integral to services like OneDrive, Google Drive, and iCloud, and remains a core Windows component, even if none of those apps were installed,” said Adam Barnett, lead software engineer at Rapid7.

    Only three of the flaws patched today earned Microsoft’s most-dire “critical” rating: Both CVE-2025-62554 and CVE-2025-62557 involve Microsoft Office, and both can exploited merely by viewing a booby-trapped email message in the Preview Pane. Another critical bug — CVE-2025-62562 — involves Microsoft Outlook, although Redmond says the Preview Pane is not an attack vector with this one.

    But according to Microsoft, the vulnerabilities most likely to be exploited from this month’s patch batch are other (non-critical) privilege escalation bugs, including:

    CVE-2025-62458 — Win32k
    CVE-2025-62470 — Windows Common Log File System Driver
    CVE-2025-62472 — Windows Remote Access Connection Manager
    CVE-2025-59516 — Windows Storage VSP Driver
    CVE-2025-59517 — Windows Storage VSP Driver

    Kev Breen, senior director of threat research at Immersive, said privilege escalation flaws are observed in almost every incident involving host compromises.

    “We don’t know why Microsoft has marked these specifically as more likely, but the majority of these components have historically been exploited in the wild or have enough technical detail on previous CVEs that it would be easier for threat actors to weaponize these,” Breen said. “Either way, while not actively being exploited, these should be patched sooner rather than later.”

    One of the more interesting vulnerabilities patched this month is CVE-2025-64671, a remote code execution flaw in the Github Copilot Plugin for Jetbrains AI-based coding assistant that is used by Microsoft and GitHub. Breen said this flaw would allow attackers to execute arbitrary code by tricking the large language model (LLM) into running commands that bypass the guardrails and add malicious instructions in the user’s “auto-approve” settings.

    CVE-2025-64671 is part of a broader, more systemic security crisis that security researcher Ari Marzuk has branded IDEsaster (IDE  stands for “integrated development environment”), which encompasses more than 30 separate vulnerabilities reported in nearly a dozen market-leading AI coding platforms, including Cursor, Windsurf, Gemini CLI, and Claude Code.

    The other publicly-disclosed vulnerability patched today is CVE-2025-54100, a remote code execution bug in Windows Powershell on Windows Server 2008 and later that allows an unauthenticated attacker to run code in the security context of the user.

    For anyone seeking a more granular breakdown of the security updates Microsoft pushed today, check out the roundup at the SANS Internet Storm Center. As always, please leave a note in the comments if you experience problems applying any of this month’s Windows patches.



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  • Abusing DLLs EntryPoint for the Fun

    Abusing DLLs EntryPoint for the Fun


    In the Microsoft Windows ecosystem, DLLs (Dynamic Load Libraries) are PE files like regular programs. One of the main differences is that they export functions that can be called by programs that load them. By example, to call RegOpenKeyExA(), the program must first load the ADVAPI32.dll. A PE files has a lot of headers (metadata) that contain useful information used by the loader to prepare the execution in memory. One of them is the EntryPoint, it contains the (relative virtual) address where the program will start to execute.



    In case of a DLL, there is also an entry point called logically the DLLEntryPoint. The code located at this address will be executed when the library is (un)loaded. The function executed is called DllMain()[1] and expects three parameters:

    
    BOOL WINAPI DllMain(
      _In_ HINSTANCE hinstDLL, 
      _In_ DWORD fdwReason, 
      _In_ LPVOID lpvReserved
    );
    

    The second parmeter indicates why the DLL entry-point function is being called:

    • DLL_PROCESS_DETACH (0)
    • DLL_PROCESS_ATTACH (1)
    • DLL_THREAD_ATTACH (2)
    • DLL_THREAD_DETACH (3)

    Note that this function is optional but it is usually implemented to prepare the environment used by the DLL like loading resources, creating variables, etc… Microsoft recommends also to avoid performing sensitive actions at that location.

    Many maware are deployed as DLLs because it’s more challenging to detect. The tool regsvr32.exe[2] is a classic attack vector because it helps to register a DLL in the system (such DLL will implement a DllRegisterServer() function). Another tool is rundll32.exe[3] that allows to call a function provided by a DLL:

    
    C:\> rundll32.exe mydll.dll,myExportedFunction

    When a suspicious DLL is being investigated, the first reflex of many Reverse Engineers is to look at the exported function(s) but don’t pay attention to the entrypoint. They look at the export table:

    This DllMain() is a very nice place where threat actors could store malicious code that will probably remains below the radar if you don’t know that this EntryPoint exists. I wrote a proof-of-concept DLL that executes some code once loaded (it will just pop up a calc.exe). Here is the simple code:

    
    // evildll.cpp
    #include 
    #pragma comment(lib, "user32.lib")
    
    extern "C" __declspec(dllexport) void SafeFunction() {
        // Simple exported function
        MessageBoxA(NULL, "SafeFunction() was called!", "evildll", MB_OK | MB_ICONINFORMATION);
    }
    
    BOOL APIENTRY DllMain(HMODULE hModule,
                          DWORD  ul_reason_for_call,
                          LPVOID lpReserved) {
        switch (ul_reason_for_call) {
            case DLL_PROCESS_ATTACH:
            {
                // Optional: disable thread notifications to reduce overhead
                DisableThreadLibraryCalls(hModule);
    
                STARTUPINFOA si{};
                PROCESS_INFORMATION pi{};
                si.cb = sizeof(si);
                char cmdLine[] = "calc.exe";
    
                BOOL ok = CreateProcessA(NULL, cmdLine, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi);
                if (ok) {
                    CloseHandle(pi.hThread);
                    CloseHandle(pi.hProcess);
                } else {
                    // optional: GetLastError() handling/logging
                }
                break;
            }
            case DLL_THREAD_ATTACH:
            case DLL_THREAD_DETACH:
            case DLL_PROCESS_DETACH:
                break;
        }
        return TRUE;
    }

    And now, a simple program used to load my DLL:

    
    // loader.cpp
    #include 
    #include 
    
    typedef void (*SAFEFUNC)();
    
    int main()
    {
        // Load the DLL
        HMODULE hDll = LoadLibraryA("evildll.dll");
        if (!hDll)
        {
            printf("LoadLibrary failed (error %lu)\n", GetLastError());
            return 1;
        }
        printf("[+] DLL loaded successfully\n");
    
        // Resolve the function
        SAFEFUNC SafeFunction = (SAFEFUNC)GetProcAddress(hDll, "SafeFunction");
        if (!SafeFunction)
        {
            printf("GetProcAddress failed (error %lu)\n", GetLastError());
            FreeLibrary(hDll);
            return 1;
        }
        printf("[+] SafeFunction() resolved\n");
    
        // Call the function
        SafeFunction();
    
        // Unload DLL
        FreeLibrary(hDll);
    
        return 0;
    }

    Let’s compile the DLL, the loader and execute it:

    When the DLL is loaded with LoadLibraryA(), the calc.exe process is spawned automatically, even if no DLL function is invoked!

    Conclusion: Always have a quick look at the DLL entry point!

    [1] https://learn.microsoft.com/en-us/windows/win32/dlls/dllmain

    [2] https://attack.mitre.org/techniques/T1218/010/

    [3] https://attack.mitre.org/techniques/T1218/011/

    Xavier Mertens (@xme)

    Xameco

    Senior ISC Handler – Freelance Cyber Security Consultant

    PGP Key



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  • New Advanced Phishing Kits Use AI and MFA Bypass Tactics to Steal Credentials at Scale

    New Advanced Phishing Kits Use AI and MFA Bypass Tactics to Steal Credentials at Scale


    Cybersecurity researchers have documented four new phishing kits named BlackForce, GhostFrame, InboxPrime AI, and Spiderman that are capable of facilitating credential theft at scale.

    BlackForce, first detected in August 2025, is designed to steal credentials and perform Man-in-the-Browser (MitB) attacks to capture one-time passwords (OTPs) and bypass multi-factor authentication (MFA). The kit is sold on Telegram forums for anywhere between €200 ($234) and €300 ($351).

    The kit, according to Zscaler ThreatLabz researchers Gladis Brinda R and Ashwathi Sasi, has been used to impersonate over 11 brands, including Disney, Netflix, DHL, and UPS. It’s said to be in active development.

    “BlackForce features several evasion techniques with a blocklist that filters out security vendors, web crawlers, and scanners,” the company said. “BlackForce remains under active development. Version 3 was widely used until early August, with versions 4 and 5 being released in subsequent months.”

    Phishing pages connected to the kit have been found to use JavaScript files with what has been described as “cache busting” hashes in their names (e.g., “index-[hash].js”), thereby forcing the victim’s web browser to download the latest version of the malicious script instead of using a cached version.

    In a typical attack using the kit, victims who click on a link are redirected to a malicious phishing page, after which a server-side check filters out crawlers and bots, before serving them a page that’s designed to mimic a legitimate website. Once the credentials are entered on the page, the details are captured and sent to a Telegram bot and a command-and-control (C2) panel in real-time using an HTTP client called Axios.

    When the attacker attempts to log in with the stolen credentials on the legitimate website, an MFA prompt is triggered. At this stage, the MitB techniques are used to display a fake MFA authentication page to the victim’s browser through the C2 panel. Should the victim enter the MFA code on the bogus page, it’s collected and used by the threat actor to gain unauthorized access to their account.

    “Once the attack is complete, the victim is redirected to the homepage of the legitimate website, hiding evidence of the compromise and ensuring the victim remains unaware of the attack,” Zscaler said.

    GhostFrame Fuels 1M+ Stealth Phishing Attacks

    Another nascent phishing kit that has gained traction since its discovery in September 2025 is GhostFrame. At the heart of the kit’s architecture is a simple HTML file that appears harmless while hiding its malicious behavior within an embedded iframe, which leads victims to a phishing login page to steal Microsoft 365 or Google account credentials.

    “The iframe design also allows attackers to easily switch out the phishing content, try new tricks or target specific regions, all without changing the main web page that distributes the kit,” Barracuda security researcher Sreyas Shetty said. “Further, by simply updating where the iframe points, the kit can avoid being detected by security tools that only check the outer page.”

    Attacks using the GhostFrame kit commence with typical phishing emails that claim to be about business contracts, invoices, and password reset requests, but are designed to take recipients to the fake page. The kit uses anti-analysis and anti-debugging to prevent attempts to inspect it using browser developer tools, and generates a random subdomain each time someone visits the site.

    Cybersecurity

    The visible outer pages come with a loader script that’s responsible for setting up the iframe and responding to any messages from the HTML element. This can include changing the parent page’s title to impersonate trusted services, modifying the site favicon, or redirecting the top-level browser window to another domain.

    In the final stage, the victim is sent to a secondary page containing the actual phishing components through the iframe delivered via the constantly changing subdomain, thereby making it harder to block the threat. The kit also incorporates a fallback mechanism in the form of a backup iframe appended at the bottom of the page in the event the loader JavaScript fails or is blocked.

    InboxPrime AI Phishing Kit Automates Email Attacks

    If BlackForce follows the same playbook as other traditional phishing kits, InboxPrime AI goes a step further by leveraging artificial intelligence (AI) to automate mass mailing campaigns. It’s advertised on a 1,300-member-strong Telegram channel under a malware-as-a-service (MaaS) subscription model for $1,000, granting purchasers a perpetual license and full access to the source code.

    “It is designed to mimic real human emailing behavior and even leverages Gmail’s web interface to evade traditional filtering mechanisms,” Abnormal researchers Callie Baron and Piotr Wojtyla said.

    “InboxPrime AI blends artificial intelligence with operational evasion techniques and promises cybercriminals near-perfect deliverability, automated campaign generation, and a polished, professional interface that mirrors legitimate email marketing software.”

    The platform employs a user-friendly interface that allows customers to manage accounts, proxies, templates, and campaigns, mirroring commercial email automation tools. One of its core features is a built-in AI-powered email generator, which can produce entire phishing emails, including the subject lines, in a manner that mimics legitimate business communication.

    In doing so, these services further lower the barrier to entry for cybercrime, effectively eliminating the manual work that goes into drafting such emails. In its place, attackers can configure parameters, such as language, topic, or industry, email length, and desired tone, which the toolkit uses as inputs to generate convincing lures that match the chosen theme.

    What’s more, the dashboard enables users to save the produced email as a reusable template, complete with support for spintax to create variations of the email messages by substituting certain template variables. This ensures that no two phishing emails look identical and helps them bypass signature-based filters that look for similar content patterns.

    Some of the other supported features in InboxPrime AI are listed below –

    • A real-time spam diagnostic module that can analyze a generated email for common spam-filter triggers and suggest precise corrections
    • Sender identity randomization and spoofing, enabling attackers to customize display names for each Gmail session

    “This industrialization of phishing has direct implications for defenders: more attackers can now launch more campaigns with more volume, without any corresponding increase in defender bandwidth or resources,” Abnormal said. “This not only accelerates campaign launch time but also ensures consistent message quality, enables scalable, thematic targeting across industries, and empowers attackers to run professional-looking phishing operations without copywriting expertise.”

    Spiderman Creates Pixel-Perfect Replicas of European Banks

    The third phishing kit that has come under the cybersecurity radar is Spiderman, which permits attackers to target customers of dozens of European banks and online financial services providers, such as Blau, CaixaBank, Comdirect, Commerzbank, Deutsche Bank, ING, O2, Volksbank, Klarna, and PayPal.

    “Spiderman is a full-stack phishing framework that replicates dozens of European banking login pages, and even some government portals,” Varonis researcher Daniel Kelley said. “Its organized interface provides cybercriminals with an all-in-one platform to launch phishing campaigns, capture credentials, and manage stolen session data in real-time.”

    Cybersecurity

    What’s notable about the modular kit is that its seller is marketing the solution in a Signal messenger group that has about 750 members, marking a departure from Telegram. Germany, Austria, Switzerland, and Belgium are the primary targets of the phishing service.

    Like in the case of BlackForce, Spiderman utilizes various techniques like ISP allowlisting, geofencing, and device filtering to ascertain that only the intended targets can access the phishing pages. The toolkit is also equipped to capture cryptocurrency wallet seed phrases, intercept OTP and PhotoTAN codes, and trigger prompts to gather credit card data.

    “This flexible, multi-step approach is particularly effective in European banking fraud, where login credentials alone often aren’t enough to authorize transactions,” Kelley explained. “After capturing credentials, Spiderman logs each session with a unique identifier so the attacker can maintain continuity through the entire phishing workflow.”

    Hybrid Salty-Tycoon 2FA Attacks Spotted

    BlackForce, GhostFrame, InboxPrime AI, and Spiderman are the latest additions to a long list of phishing kits like Tycoon 2FA, Salty 2FA, Sneaky 2FA, Whisper 2FA, Cephas, and Astaroth (not to be confused with a Windows banking trojan of the same name) that have emerged over the past year.

    In a report published earlier this month, ANY.RUN said it observed a new Salty-Tycoon hybrid that’s already bypassing detection rules tuned to either of them. The new attack wave coincides with a sharp drop in Salty 2FA activity in late October 2025, with early stages matching Salty2FA, while later stages load code that reproduces Tycoon 2FA’s execution chain.

    “This overlap marks a meaningful shift; one that weakens kit-specific rules, complicates attribution, and gives threat actors more room to slip past early detection,” the company said.

    “Taken together, this provides clear evidence that a single phishing campaign, and, more interestingly, a single sample, contains traces of both Salty2FA and Tycoon, with Tycoon serving as a fallback payload once the Salty infrastructure stopped working for reasons that are still unclear.”



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