An assembly also contains a manifest that details, among other things, metadata about the assembly's name and version. This can be achieved through either prior knowledge or exploitation of vulnerabilities present in older, unpatched versions of Telerik released between 2007 and 2017. The control addresses the limitation to perform file uploads with plain post backs only, and supports web farm scenarios, as well as internal validation, using its http handler for this purpose. By selecting these links, you will be leaving NIST webspace. We use rev_shell.c below, a program that launches a reverse shell as a thread when the DLL is loaded; the threaded nature of this program prevents the shell process from blocking the web application's user interface while running: rev_shell.c. not necessarily endorse the views expressed, or concur with Now that Telerik has released a patch and security advisory for this vulnerability, affected users should do their part by updating and securely configuring their applications. This Metasploit module exploits the.NET deserialization vulnerability within the RadAsyncUpload (RAU) component of Telerik UI ASP.NET AJAX that is identified as CVE-2019-18935. Thanks to Markus Wulftange (@mwulftange) of Code White GmbH for initially discovering this insecure deserialization vulnerability and for summarizing his research. This batch script accomplishes the following: The assembly's name as specified in link /out is baked into the assembly's manifest, and will persist even if the file name changes on disk. If this type is controlled by an attacker, this can lead to a dangerous scenario where the attacker may specify the type to be a gadget. Telerik recently announced that there is a security vulnerability with all versions of Telerik.Web.UI.dll assembly prior to 2017.2.621.. Sitecore includes documentation on how to secure Telerik for Sitecore 8.x (edit: note that the article referenced in the accepted answer provides better information than this one), but there appears to be no documentation for earlier versions. UPDATE: Caleb presented on this topic at 2020 DerpCon, which you can watch below. Denotes Vulnerable Software Create a bare C# class in empty.cs to constitute the managed portion of your mixed mode assembly: Then, in a Windows environment with Visual Studio installed, open a command prompt and run build_dll.bat sleep.c: build_dll.bat. NIST does Please let us know, Announcement and This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Calculator CVSS AsyncUploadHandler uses the type specified within rauPostData to prepare .NET's JavaScriptSerializer.Deserialize() method to properly deserialize the object. the new file to the old one. The following exploit script leverages the core RadAsyncUpload encryption logic provided by Paul Taylor's RAU_crypto.py to craft an encrypted rauPostData POST parameter; this enables access to the vulnerable AsyncUploadHandler class through which we can upload files and deserialize arbitrary object types. If an attacker specified an arbitrary value for the TempTargetFolder variable within the encrypted rauPostData POST parameter, it would effectively allow file uploads to any directory where the web server had write permissions. The upload process requires that the files are uploaded to a … For more details, please refer to Implications of Loading .NET Assemblies and Friday the 13th JSON Attacks. CVE-2014-2217 is outside of the scope of this post, but it's important that we mention it here, since Telerik responded to this issue by encrypting a particular portion of file upload requests to prevent attackers from tampering with sensitive settings. Note that I use C, rather than C++, because I've encountered rare occasions where I was unable to execute compiled C++ code on a remote server. Telerik Web UI RadAsyncUpload Deserialization Description The Telerik UI component for ASP.NET AJAX (versions 2019.3.917 and older) are deserializing JSON objects in an insecure manner that results in arbitrary remote code execution on the software's underlying host. It insecurely deserializes JSON objects in a manner that results in arbitrary remote code execution on the software's underlying host. It is awaiting reanalysis which may result in further changes to the information provided. (In 2019.3.1023 but not earlier versions, a non-default setting can prevent exploitation.). Controls / Async Upload. Since uploading a file with RadAsyncUpload requires providing the correct version of Telerik UI, you can use Paul Taylor’s RAU_crypto exploit to submit file upload requests with known-vulnerable versions until you find one that works: When the file upload succeeds, you'll see a JSON response containing some encrypted data about the uploaded file: Now that you’ve verified that the handler is registered and the software is using a vulnerable version, you can proceed to exploit the vulnerability. Policy | Security A vulnerability in Telerik UI for ASP.NET could allow for arbitrary code execution within the context of a privileged process. Telerik. AsyncUpload Overview. The vulnerabilities affect Telerik DialogHandler and RadAsyncUpload. In 2019.3.1023, but not earlier versions, a non-default setting can prevent exploitation. RadAsyncUpload will upload your file to a temporary directory whose location is under your control. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. inferences should be drawn on account of other sites being The following sections will walk through two vulnerabilities in RadAsyncUpload, which is a file handler in Telerik UI for ASP.NET AJAX that enables uploading files asynchronously (i.e., without reloading the existing page). This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Learn and educate yourself with malware analysis, cybercrime python >= 3.6 with pycryptodome (https://www.pycryptodome.org/en/latest/src/installation.html) - installed with pip3 install pycryptodome or pip3 install pycryptodomex Information Quality Standards, Business Modify the configuration to allow file uploading anywhere they like on the target web server. In order to do so the module must upload a mixed mode.NET assembly DLL which is then loaded through the deserialization flaw. After using the aforementioned unrestricted file upload vulnerability to upload a malicious mixed mode assembly DLL, an attacker may follow up with a second request to force JavaScriptSerializer to deserialize an object of type System.Configuration.Install.AssemblyInstaller. ", Last-Modified: Wed, 20 Feb 2013 00:00:00 GMT, VGhpcyBpc24ndCByZWFsIGRhdGEsIGJ1dCB0aGUgQmFzZTY0LWVuY29kZWQgZGF0YSBsb29rcyBqdXN0IGxpa2UgdGhpcy4=, "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat", Sets environment variables to compile both 32- and 64-bit code, The following exploit script leverages the core RadAsyncUpload encryption logic provided by Paul Taylor's, 'Telerik.Web.UI.AsyncUploadConfiguration, Telerik.Web.UI, Version=', ', Culture=neutral, PublicKeyToken=121fae78165ba3d4', 'System.Configuration.Install.AssemblyInstaller, System.Configuration.Install, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. Integrity Summary | NIST Please let us know. (As of 2020.1.114, a default setting prevents the exploit. It is the most fundamental unit of deployment for a .NET application, and can be implemented as an EXE or DLL file. @bao7uo wrote all of the logic for breaking RadAsyncUpload encryption, which enabled manipulating the file upload configuration object in rauPostData and subsequently exploiting insecure deserialization of that object. Since Telerik has just responded to this issue by releasing a security advisory for CVE-2019-18935, we're sharing our knowledge about it here in an effort to raise awareness about the severity of this vulnerability, and to encourage affected users to patch and securely configure this software. C# is often considered a managed language as it's typically compiled to CIL (Common Intermediate Language—a platform-independent language between source code and final native machine code) to be run under the CLR. CIL, in turn, is compiled into native code by a just-in-time compiler within the CLR. Exploitation can result in remote code execution. After covering the context of those two CVEs, we’ll dive deeper into the insecure deserialization vulnerability to learn if it affects your system, how the exploit works, and how you can patch systems against this vulnerability. In order to do so the module must upload a mixed mode.NET assembly DLL which is then loaded through the deserialization flaw. Perform configurable asynchronous uploads of single or multiple files using RadAsyncUpload for ASP.NET AJAX. | USA.gov, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, Information This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Please address comments about this page to nvd@nist.gov. The Telerik security advisory tells you what you need to know, but we’ll repeat the most important parts here: This write-up has demonstrated how an attacker can chain exploits for unrestricted file upload (CVE-2017-11317) and insecure deserialization (CVE-2019-18935) vulnerabilities to execute arbitrary code on a remote machine. The issues were fixed in Telerik's public assemblies starting from 2017.2.711. The CLR is an application virtual machine that provides services such as security, memory management, and exception handling. # One extra input is required for the page to process the request. For more information … Now with our background knowledge of the prerequisite unrestricted file upload vulnerability (CVE-2017-11317), the deserialization vulnerability itself, and mixed mode assemblies, we can now explore this exploit step by step. An unauthenticated, remote attacker can exploit this, via specially crafted data, to execute arbitrary code. A remote code execution (RCE) gadget's properties allow it to perform operations that facilitate executing arbitrary code. the facts presented on these sites. For those who are too lazy to read the entire post and just want the facts: Affected control: RadAsyncUpload; Affected versions: Release Q3 … Progress Telerik UI for ASP.NET AJAX up to and including 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. A gadget is a class within the executing scope of the application that, as a side effect of being instantiated and modified via setters or field assignment, has special properties that make it useful during deserialization. Exploitation can result in remote code execution. Current Description Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a.NET deserialization vulnerability in the RadAsyncUpload function. - Your app will be safe from the known vulnerabiltieis if the Telerik.Web.UI.dll assembly is released before Q1 2010 (version 2010.1.309) or … these sites. About RadAsyncUpload for ASP.NET AJAX. 1-888-282-0870, Sponsored by We use, https://github.com/infoskirmish/Window-Tools/blob/master/Simple%20Reverse%20Shell/shell.c. rauPostData, they could: In summary, in order to exploit insecure deserialization (CVE-2019-18935) in this file handler, we must first break the encryption that the handler uses to protect file upload POST requests (CVE-2017-11317). A simple program, sleep.c, will do just that. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. If the application attempts to load the resulting malformed DLL, it can cause the application to crash—so it's extremely important that you use a unique file name each time you upload a file to the target. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. RadAsyncUpload component in not used in the web app, is the app still vulnerable to the known vulnerabilities in the RadAsyncUpload? It's crucial that the assembly is uniquely named at linking time since a .NET application will only load an assembly once with a given name. This vulnerability has been modified since it was last analyzed by the NVD. The attack often uses the known vulnerabilities CVE-2017-11317 and CVE-2019-18935 They are already fixed, when they were found, and Progress notified customers with instructions and mitigation steps. [0-9]*)+ (and make sure you check the "Regex" box). Environmental As we continue to identify and understand this class of vulnerabilities, it’s important that vendors and users employ timely communication to combat the risk posed by vulnerable software. This script also ensures that each uploaded file has a unique name on disk. Until R2 2017 SP1 (v2017.2.621), RadAsyncUpload's AsyncUploadHandler was configured with a hard-coded key that was used to encrypt form data in file upload requests. Exploitation can result in remote code execution. Validated Tools SCAP No Telerik.Web.UI in Progress Telerik UI for ASP.NET AJAX before R1 2017 and R2 before R2 2017 SP2 uses weak RadAsyncUpload encryption, which allows remote attackers to perform arbitrary file uploads or execute arbitrary code. CVE-2019-18935: Remote Code Execution via Insecure Deserialization in Telerik UI, PrivateKeyForEncryptionOfRadAsyncUploadConfiguration, "RadAsyncUpload handler is registered succesfully, however, it may not be accessed directly. Thanks @mwulftange initially discovered this vulnerability. The vulnerability report states the following - Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. RadAsyncUpload has previously been the subject of a number of vulnerabilities, including CVE-2014-2217, which is a path traversal vulnerability in the handler's file upload POST requests that results in unrestricted file upload. The version of Telerik UI for ASP.NET AJAX installed on the remote Windows host is affected by multiple vulnerabilities in Telerik.Web.UI.dll. In recent years, insecure deserialization has emerged as an effective attack vector for executing arbitrary code in object-oriented programming frameworks. Please refer to @straightblast's write-up for a detailed breakdown of rauPostData's structure (and of this vulnerability in general), and Telerik's security advisory for how this vulnerability was remediated. Before attempting to exploit Telerik UI for ASP.NET AJAX, confirm first that the file upload handler is registered: Additionally, you’ll need to confirm that the web application is using a vulnerable version of this software. All code references in this post are also available in the CVE-2019-18935 GitHub repo. Vulnerability Assessments. If the application using RadAsyncUpload does not require authentication, then you can usually find the UI version buried somewhere in the HTML source of the application's home page. Telerik ASP.NET File Explorer - Ready-to-use file explorer control, high performance and rich customization options. Conveniently, Telerik publishes a release history that details all major software versions since April 2007. Fear Act Policy, Disclaimer Links to Telerik UI security vulnerablities CVE-2014-2217, CVE-2017-11317 and CVE-2019-18935 were added to References on 12-May-20. This means that an assembly "sleep_123.dll" may cause the application to sleep the first time that DLL is loaded through deserialization, but it certainly won't successfully load again; you'll need to rerun build_dll.bat to generate a new assembly for each exploit attempt on the same server. sites that are more appropriate for your purpose. They are present in one of the assemblies distributed with Sitefinity CMS - Telerik.Web.UI.dll. RadAsyncUpload introduced in Q1 2010 (version 2010.1.309) offers asynchronous upload capability while maintaining the look of the regular RadUpload control. | Science.gov Telerik security advisory A prerequisite for exploitation of this vulnerability is a malicious actor having knowledge of the Telerik RadAsyncUpload encryption keys. Disclaimer | Scientific Exploitation can result in remote code execution. Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. V2 Calculator, CPE Dictionary CPE Search CPE Statistics SWID, Checklist (NCP) Repository 'Exploit for CVE-2019-18935, a .NET deserialization vulnerability in Telerik UI for ASP.NET AJAX. Now that we've verified that we can exploit this vulnerable version of Telerik UI for ASP.NET AJAX, we can instead exploit it with a DLL that spawns a reverse shell to connect back to a server that we control. ', "just test file upload, don't exploit deserialization vuln", 'https:///Telerik.Web.UI.WebResource.axd?type=rau', Now that we've verified that we can exploit this vulnerable version of Telerik UI for ASP.NET AJAX, we can instead exploit it with a DLL that spawns a reverse shell to connect back to a server that we control. If you happen to upload two files with the same name (we're talking about file names on disk, not assembly names in a manifest), RadAsyncUpload will append (not overwrite!) This module exploits the.NET deserialization vulnerability within the RadAsyncUpload (RAU) component of Telerik UI ASP.NET AJAX that is identified as CVE-2019-18935. An attacker who successfully exploits the vulnerability can … Telerik provided fixes to Sitecore as custom updates for assembly versions that are compatible with Sitecore CMS/XP. Before uploading the DLL, it's important to understand what's going to happen on disk on the remote server. Telerik.Web.UI.RadAsyncUpload.Handling.Arbitrary.File.Upload Description This indicates an attack attempt to exploit an Arbitrary File Upload vulnerability in Telerik UI for ASP.NET AJAX components. There may be other web ), Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. So, "managed" code is written to run exclusively under the CLR, a layer that wraps native compiled code to prevent some common problems (e.g., buffer overflows) and abstract away some platform-specific implementation details to make code more portable. Webmaster | Contact Us Notice | Accessibility | Our Other Offices, NVD Dashboard News Email List FAQ Visualizations, Search & Statistics Full Listing Categories Data Feeds Vendor CommentsCVMAP, CVSS V3 The attack is also targeting old Telerik UI vulnerabilities that have already been patched. If attackers were able to break the encryption protecting the configuration object in RadAsyncUpload has previously been the subject of a number of vulnerabilities, including CVE-2014-2217, which is a path traversal vulnerability in the handler's file upload POST requests that results in unrestricted file upload. 800-53 Controls SCAP Big thanks again to Markus Wulftange (@mwulftange) and Paul Taylor (@bao7uo), both of whom paved the way for this work through their prior research. For further reading, check out this article about injecting .NET assemblies which provides a useful .NET primer, and a related article on mixed assemblies. This is a potential security issue, you are being redirected to https://nvd.nist.gov. Thanks also to Paul Taylor (@bao7uo) who, after authoring an exploit to break encryption for an unrestricted file upload vulnerability, developed an extended custom payload feature that was instrumental in triggering this deserialization vulnerability. If the application does require authentication, then you may be able to determine the software version via brute force. Information Quality Standards. This issue (CVE-2017-11317) is a well-known vulnerability and has already been reported on. Discussion Lists, NIST            If you're unfamiliar with the .NET framework, then these terms may not mean anything to you. For example, a JavaScript resource bundled with UI for ASP.NET AJAX Q1 2013 (v2013.1.220, released on February 20, 2013) will read Last-Modified: Wed, 20 Feb 2013 00:00:00 GMT in the HTTP response header for that file. You can also accomplish this with cURL: If that doesn't work, you can alternatively search for the string