ED 25-02 directs all Federal Civilian Executive Branch (FCEB) agencies with Microsoft Exchange hybrid environments to implement required mitigations by 9:00 AM EDT on Monday, August 11, 2025.
This vulnerability presents significant risk to all organizations operating Microsoft Exchange hybrid-joined configurations that have not yet implemented the April 2025 patch guidance.
Vulnerabilities: Cleartext Transmission of Sensitive Information, Download of Code Without Integrity Check, Observable Discrepancy, Improper Restriction of Excessive Authentication Attempts
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to intercept and manipulate critical data, install malicious firmware, hijack device access, and gain unauthorized control over the system.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following EG4 Electronics inverters are affected:
The MOD3 command traffic between the monitoring application and the inverter is transmitted in plaintext without encryption or obfuscation. This vulnerability may allow an attacker with access to a local network to intercept, manipulate, replay, or forge critical data, including read/write operations for voltage, current, and power configuration, operational status, alarms, telemetry, system reset, or inverter control commands, potentially disrupting power generation or reconfiguring inverter settings.
The affected product allows firmware updates to be downloaded from EG4’s website, transferred via USB dongles, or installed through EG4’s Monitoring Center (remote, cloud-connected interface) or via a serial connection, and can install these files without integrity checks. The TTComp archive format used for the firmware is unencrypted and can be unpacked and altered without detection.
The public-facing product registration endpoint server responds differently depending on whether the S/N is valid and unregistered, valid but already registered, or does not exist in the database. Combined with the fact that serial numbers are sequentially assigned, this allows an attacker to gain information on the product registration status of different S/Ns.
The affected product does not limit the number of attempts for inputting the correct PIN for a registered product, which may allow an attacker to gain unauthorized access using brute-force methods if they possess a valid device serial number. The API provides clear feedback when the correct PIN is entered. This vulnerability was patched in a server-side update on April 6, 2025.
Anthony Rose of BC Security reported these vulnerabilities to CISA.
4. MITIGATIONS
EG4 has acknowledged the vulnerabilities and is actively working on a fix, including new hardware expected to release by October 15, 2025. Until then, EG4 will actively monitor all installed systems and work with affected users on a case-by-case basis if anomalies are observed.
Note that CVE-2025-46414 was fixed on April 6, 2025. No user action was or is necessary.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
CISA also recommends users take the following measures to protect themselves from social engineering attacks:
Do not click web links or open attachments in unsolicited email messages.
Vulnerability: Missing Authentication for Critical Function
2. RISK EVALUATION
Successful exploitation of this vulnerability could result in an attacker gaining access to the device, locking out authorized users, or disrupting operations.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following version of ARC Solo, a monitoring and control device primariliy used in broadcasting, is affected:
The device’s password change mechanism can be utilized without proper authentication procedures, allowing an attacker to take over the device. A password change request can be sent directly to the device’s HTTP endpoint without providing valid credentials. The system does not enforce proper authentication or session validation, allowing the password change to proceed without verifying the request’s legitimacy.
Souvik Kandar of MicroSec (microsec.io) reported this vulnerability to CISA.
4. MITIGATIONS
Burk Technology recommends users update their ARC Solo devices to Version v1.0.62 or later. The upgrade can be downloaded from the Burk Technology website.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
A TLS vulnerability exists in the phone application used to manage a connected device. The phone application accepts self-signed certificates when establishing TLS communication which may result in man-in-the-middle attacks on untrusted networks. Captured communications may include user credentials and sensitive session tokens.
Dreame Technology did not respond to CISA’s request for coordination. Contact Dreame Technology directly for more information. Note that MOVA is a subsidiary of Dreame Technology.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.
Vulnerability: Improper Limitation of a Pathname to a Restricted Directory
2. RISK EVALUATION
Successful exploitation of this vulnerability may allow a remote attacker to read or write files on the affected device.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Delta Electronics reports the following versions of DIAView industrial automation management system for providing real-time system control are affected:
Delta Electronics offers users the following general recommendations:
Do not click on untrusted Internet links or open unsolicited attachments in emails.
Avoid exposing control systems and equipment to the Internet.
Place control system networks and remote devices behind firewalls, and isolate them from the business network.
When remote access is required, use a secure access method, such as a virtual private network (VPN).
If you have any product-related support concerns, contact Delta via the portal page for any information or materials you may require.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Commercial Facilities, Government Facilities, Transportation Systems, Energy
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Ireland
3.4 RESEARCHER
Johnson Controls reported this vulnerability to CISA.
4. MITIGATIONS
Johnson Controls recommends users update to the latest version. Successful exploitation of CVE-2025-43867 could trigger CVEs CVE-2025-3936 through CVE-2025-3945.
For systems running version 14.10.10, apply the 14.10.11 patch from the software portal.
For systems running version 14.14.1, apply the 14.14.2 patch from the software portal.
Note: FX 14.10.10 contains Niagara 4.10u10
Note: FX 14.14.1 contains Niagara 4.14u1
Login credentials are required to access the software portal.
For more detailed mitigation instructions, visit Johnson Controls Product Security Advisory JCI-PSA-2025-09 v1
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
By default, the Packet Power Monitoring and Control Web Interface do not enforce authentication mechanisms. This vulnerability could allow unauthorized users to access and manipulate monitoring and control functions.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
Vulnerabilities: Use of Hard-coded Credentials, Command Injection, Predictable Seed in Pseudo-Random Number Generator (PRNG).
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow attackers to gain unauthorized administrative access using hard-coded credentials, escalate privileges to take full control of the device, modify system settings, disrupt solar energy production, interfere with safety mechanisms, execute arbitrary commands via command injection, cause service disruptions, expose sensitive data, and recreate valid session IDs to access sensitive device functions on connected solar inverter systems due to insecure session ID generation.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Cloud Connect Advanced are affected:
Tigo Energy’s Cloud Connect Advanced (CCA) device contains hard-coded credentials that allow unauthorized users to gain administrative access. This vulnerability enables attackers to escalate privileges and take full control of the device, potentially modifying system settings, disrupting solar energy production, and interfering with safety mechanisms.
Tigo Energy’s CCA is vulnerable to a command injection vulnerability in the /cgi-bin/mobile_api endpoint when the DEVICE_PING command is called, allowing remote code execution due to improper handling of user input. When used with default credentials, this enables attackers to execute arbitrary commands on the device that could cause potential unauthorized access, service disruption, and data exposure.
Tigo Energy’s CCA device is vulnerable to insecure session ID generation in their remote API. The session IDs are generated using a predictable method based on the current timestamp, allowing attackers to recreate valid session IDs. When combined with the ability to circumvent session ID requirements for certain commands, this enables unauthorized access to sensitive device functions on connected solar optimization systems.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
CISA published a Malware Analysis Report (MAR) with analysis and associated detection signatures on files related to Microsoft SharePoint vulnerabilities:
Cyber threat actors have chained CVE-2025-49704 and CVE-2025-49706 (in an exploit chain publicly known as “ToolShell”) to gain unauthorized access to on-premises SharePoint servers. CISA analyzed six files including two Dynamic Link-Library (.DLL), one cryptographic key stealer, and three web shells. Cyber threat actors could leverage this malware to steal cryptographic keys and execute a Base64-encoded PowerShell command to fingerprint host system and exfiltrate data.
The information in this report is being provided “as is” for informational purposes only. CISA does not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA.
This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.
This document is marked TLP:CLEAR–Recipients may share this information without restriction. Sources may use TLP:CLEAR when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:CLEAR information may be shared without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.cisa.gov/tlp.
Summary
Description
CISA received six files related to Microsoft SharePoint vulnerabilities: CVE-2025-49704 [CWE-94: Code Injection], CVE-2025-49706 [CWE-287: Improper Authentication], CVE-2025-53770 [CWE-502: Deserialization of Trusted Data], and CVE-2025-53771 [CWE-287: Improper Authentication]. According to Microsoft, cyber threat actors have chained CVE-2025-49706 (a network spoofing vulnerability) and CVE-2025-49704 (a remote code execution (RCE) vulnerability) in an exploit chain known as “ToolShell” to gain unauthorized access to on-premise SharePoint servers. Microsoft has not confirmed exploitation of CVE-2025-53771; however, CISA assesses exploitation is likely because it can be chained with CVE-2025-53770 to bypass previously disclosed vulnerabilities CVE-2025-49704 and CVE-2025-49706.
The analysis includes two Base64 encoded .NET Dynamic-link Library (DLL) binaries and four Active Server Page Extended [ASPX] files. The decoded DLLs are designed to retrieve machine key settings within an ASP[.]NET application’s configuration and add the retrieved machine key values to the Hypertext Transfer Protocol (HTTP) response header.
The first ASPX file is used to retrieve and output machine key information from an ASP[.]NET application’s configuration. The next ASPX file contains a command-line instruction used to execute a PowerShell command. The PowerShell command is designed to Base64 decode and install a malicious ASPX webshell on disk. The webshell is used to handle various web-related operations, including setting and retrieving HTTP cookies, command execution and uploading files. The remaining two ASPX webshells are used to execute a command using PowerShell on the server.
############ README ############### ## Edit rules and queries as needed for your hunt and based on your environment. ## Ensure your EDR/SIEM instance has enough memory to run these AND/OR condition based queries. May take longer to run than conventional Sigma rule query. ## Do not edit “logsource-product:” unless you are editing this rule to meet specific logsources/fields and know your environment. ## TLP GREEN + Please use local installation of Sigma to convert this rule. ## TLP CLEAR may convert rules using online converter of choice. ###################################
title: Detects ToolShell CVE-2025-53770 Exploitation IOCs and Activity incident: 251133.r1 tlp: CLEAR id: aba8967f-6613-47a8-87d1-e5d7aae31e9b status: test description: Detects ToolShell CVE-2025-53770 Exploitation of SharePoint servers. Previous related CVEs are CVE-2025-49706 and CVE-2025-49704. CVE-2025-53770 is new and stealthy webshell called SharpyShell, that extracts and leaks cryptographic secrets from the SharePoint server using a simple GET request. references: – https://www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770 – https://research.eye.security/sharepoint-under-siege/ – https://x.com/codewhitesec/status/1944743478350557232/photo/1 – 251132.r1 author: CISA Code & Media Analysis date: 2025-07-21 modified: 2025-07-22 tags: – cve.2025.53770 logsource: product: cma detection: keywords: – ’92bb4ddb98eeaf11fc15bb32e71d0a63256a0ed826a03ba293ce3a8bf057a514′ – ‘107.191.58.76’ – ‘104.238.159.149’ – ‘96.9.125.147’ – ‘Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64;+rv:120.0)+Gecko/20100101+Firefox/120.0 /_layouts/SignOut.aspx’ – ‘-EncodedCommand JABiAGEAcwBlADYANABTAHQAcgBpAG4AZwAgAD0’ – ‘TEMPLATELAYOUTSspinstall0.aspx’ – ‘/_layouts/15/ToolPane.aspx DisplayMode=Edit’ – ‘/_layouts/15/spinstall0.aspx’ – ‘spinstall’ – ‘yoserial’
condition: keywords or keywords_1 and keywords_2 and keywords_3 or keywords_4 and keywords_5 and keywords_6 or keywords_7 and keywords_8 or keywords_9 and keywords_10 and keywords_11 and keywords_12 and keywords_13 and keywords_14 and keywords_15 and keywords_16 or keywords_17 and keywords_18 and keywords_19 and keywords_20 and keywords_21 or keywords_22 and keywords_23 and keywords_24 and keywords_25 or keywords_26 and keywords_27 and keywords_28
falsepositives: – Rate of FP moderate with some strings. – Use this rule in an infected environment/logs. – Analyst may need to make adjustments to the query as required. level: critical
############ README ############### ## Edit rules and queries as needed for your hunt and based on your environment. ## Ensure your EDR/SIEM instance has enough memory to run these AND/OR condition based queries. May take longer to run than conventional Sigma rule query. ## Do not edit “logsource-product:” unless you are editing this rule to meet specific logsources/fields and know your environment. ## TLP GREEN + Please use local installation of Sigma to convert this rule. ## TLP CLEAR may convert rules using online converter of choice. ###################################
condition: keywords_1 and keywords_2 and keywords_3 and keywords_4 and keywords_5 and keywords_6 or keywords_7 and keywords_8 and keywords_9 and keywords_10 and keywords_11 or keywords_12 and keywords_13 and keywords_14 or keywords_15 and keywords_16 or keywords_17 and keywords_18 and keywords_19
falsepositives: – Rate of FP low-moderate with some strings. – Use this rule in an infected environment/logs. – Analyst may need to make adjustments to the query as required. level: critical
This artifact is a 64-bit .NET DLL that contains a class named “E” (Figure 2) used to extract and concatenate machine key configuration settings within an ASP[.]NET application’s configuration. The file uses reflection to access the “MachineKeySection” from the “System.Web” assembly, which contains cryptographic keys used for validation and decryption in ASP[.]NET. The file uses reflection to get and invoke the “GetApplicationConfig” method of the “MachineKeySection” class to retrieve the “machineKey” configuration, which holds the actual key values. The file constructs a string containing the “ValidationKey”, “Validation”, “DecryptionKey”, “Decryption”, and “CompatibilityMode” properties of the “machineKeySection” and adds it as a custom header named “X-TXT-NET” to the HTTP response.
Screenshots
Figure 2 – Screenshot of the decompiled .NET assembly within a class named “E” used to extract the machine key configuration.
############ README ############### ## Edit rules and queries as needed for your hunt and based on your environment. ## Ensure your EDR/SIEM instance has enough memory to run these AND/OR condition based queries. May take longer to run than conventional Sigma rule query. ## Do not edit “logsource-product:” unless you are editing this rule to meet specific logsources/fields and know your environment. ## TLP GREEN + Please use local installation of Sigma to convert this rule. ## TLP CLEAR may convert rules using online converter of choice. ###################################
condition: keywords or keywords_1 and keywords_2 and keywords_3 or keywords_4 and keywords_5 and keywords_6 or keywords_7 and keywords_8 and keywords_9 or keywords_10 and keywords_11 and keywords_12 and keywords_13 and keywords_14 or keywords_15 and keywords_16 and keywords_17 and keywords_18 and keywords_19 and keywords_20 and keywords_21 or keywords_22 and keywords_23
falsepositives: – Rate of FP low-moderate with some strings. – Use this rule in an infected environment/logs. – Analyst may need to make adjustments to the query as required. level: critical
ssdeep Matches
No matches found.
PE Metadata
Compile Date
2025-07-22 08:33:22+00:00
Import Hash
dae02f32a21e03ce65412f6e56942daa
File Description
Internal Name
osvmhdfl.dll
Legal Copyright
Original Filename
osvmhdfl.dll
Product Version
0.0.0.0
PE Sections
MD5
Name
Raw Size
Entropy
2a11da5809d47c180a7aa559605259b5
header
512
2.545281
531ff1038e010be3c55de9cf1f212b56
.text
4608
4.532967
ef6793ef1a2f938cddc65b439e44ea07
.rsrc
1024
2.170401
403090c0870bb56c921d82a159dca5a3
.reloc
512
0.057257
Packers/Compilers/Cryptors
Microsoft Visual C# / Basic .NET
Description
This artifact is a 32-bit .NET DLL that contains a class named “E” (Figure 3) used to retrieve system and environment information, along with the machine key configuration settings (Figure 3). This class file is designed to iterate through and collect environment variables as well as retrieve and format .NET and system properties below:
–Begin System Properties– Number of logical drives Drive letters Computer name Full path of the system directory Current directory Processor count System uptime (milliseconds since start) Username Operating system version .NET version –End System Properties–
The file uses reflection to access the “MachineKeySection” from the “System.Web” assembly, which contains cryptographic keys used for validation and decryption in ASP[.]NET. The file uses reflection to invoke the “GetApplicationConfig” method of the “MachineKeySection” class to retrieve the “machineKey” configuration, which holds the actual key values. The file constructs a string containing the “ValidationKey”, “Validation”, “DecryptionKey”, “Decryption”, and “CompatibilityMode” properties of the “machineKeySection”. The gathered information and the “MachineKeySection” details are formatted into a string before written to the HTTP response (current.Response object).
Screenshots
Figure 3 – Screenshot of the decompiled .NET assembly that contains a class named “E” used to retrieve and display system and environment information, along with the machine key configuration settings.
rule CISA_251132_03 : steals_authentication_credentials exfiltrates_data { meta: author = “CISA Code & Media Analysis” incident = “251132” date = “2025-07-21” last_modified = “20250724_721” actor = “n/a” family = “n/a” capabilities = “steals-authentication-credentials exfiltrates-data” malware_type = “unknown” tool_type = “unknown” description = “Detects aspx payload samples” sha256_1 = “92bb4ddb98eeaf11fc15bb32e71d0a63256a0ed826a03ba293ce3a8bf057a514” strings: $s0 = { 4C 6F 61 64 28 22 53 79 73 74 65 6D 2E 57 65 62 } $s1 = { 43 6F 6E 66 69 67 75 72 61 74 69 6F 6E 2E 4D 61 63 68 69 6E 65 4B 65 79 53 65 63 74 69 6F 6E } $s2 = { 52 65 73 70 6F 6E 73 65 2E 57 72 69 74 65 } $s3 = { 63 67 2E 56 61 6C 69 64 61 74 69 6F 6E 4B 65 79 2B 22 7C 22 } $s4 = { 2B 63 67 2E 56 61 6C 69 64 61 74 69 6F 6E 2B } $s5 = { 2B 63 67 2E 44 65 63 72 79 70 74 69 6F 6E 4B 65 79 2B } $s6 = { 2B 63 67 2E 44 65 63 72 79 70 74 69 6F 6E 2B } $s7 = { 2B 63 67 2E 43 6F 6D 70 61 74 69 62 69 6C 69 74 79 4D 6F 64 65 } condition: all of them }
SIGMA Rule
No associated rule.
ssdeep Matches
No matches found.
Description
This artifact is a malicious ASPX file used to retrieve and output machine key information from the “MachineKeySection” of the System[.]Web[.]Configuration namespace (Figure 4). This file uses reflection to dynamically load the “System.Web” assembly and access the “MachineKeySection” class within “System.Web.Configuration”. The file invokes “GetApplicationConfig” to retrieve the “MachineKeySection” object and writes its properties including, ValidationKey, Validation, DecryptionKey, Decryption, and CompatibilityMode to the HTTP response using the “Response.Write()” method.
Screenshots
Figure 4 – Screenshot of the contents of the ASPX file used to extract configuration information from the machine key section of a web application’s Web.config file.
This artifact contains command-line instruction used to execute a PowerShell command (Figure 5). The PowerShell command decodes a Base64 encoded string into a Unicode Transformation Format-8 (UTF-8) string. The decoded content is then written to a file named “info3.aspx” (675a10e87c24….) located at c:progra~1\common~1micros~1webser~1l16templatelayouts. The output file is encoded using UTF8.
Screenshots
Figure 5 – Screenshot of the contents of the file containing command-line instruction used to execute a PowerShell command.
This artifact is a malicious ASP[.]NET web page (.aspx) that contains ASP[.]NET code embedded within an HTML structure. This file is a webshell installed by “info3.aspx” (9340bf73782….). The file handles various operations based on submitted form data or HTTP cookies. The file contains HTML code used to create forms. The forms allow the Threat Actor (TA) to enter a password and submit it using a “Login” button, enter a command into a text field, which can then be executed by clicking an “Execute” button, and upload files that includes two input fields: one for selecting a file (type=”file”) and another for text input (type=”text”) (Figure 7).
The password form element is configured for POST method and the input field is named “nYOmkVTYH2”. If the HTML form with a password is received from the TA via an HTTP POST request, the file checks if the submission form field parameter named “nYOmkVTYH2” is not null or empty. If the parameter is present and not empty, the file sets an HTTP Cookie named “wY1DC6wH4u” with a value from the form field “nYOmkVTYH2” and sets the HTTP Cookie expiration date to four days from the current time. This cookie is then added to the response. The file verifies if the HTTP cookie exists in the current HTTP request. If the cookie exists, its value is concatenated with a long hard-coded string “D&Fri2k&x5dMISTnaFq@ssyKk@rEM!98KzSKWpL4Nc8NvaA9AKdJVOtfdJ45FvbyYHxTql6kkc%qOZevc*hu^M#l#LrlNo9!7KLf”. This combined string is then hashed using SHA512. The computed hash is converted to a Base64 string and compared against a predefined Base64 encoded string “9gYs0W/reXzR+KO6J/zP6naMU9AQwZCwhmXuPyGeY2VwMkxNGBZaJQAxGS6GvQZJLSAPk8LT0PgJVU1kQQJd2zW9w==” (Figure 6). This process determines whether a user or request is authorized.
The command form element is configured for POST method and the input field is named “GTaRkhJ9wz”. If the HTML form with a command is received from the TA via an HTTP POST request, the file checks if the submission form field parameter named “GTaRkhJ9wz” is not null or empty. If the parameter is present and not empty, the file creates a new process to execute a command-line utility “cmd.exe”. The file redirects standard input, output, and error streams to capture the results of the executed command. The code writes the value of the “GTaRkhJ9wz” form parameter to the process’s standard input, executing the value as a command, and then writes “exit” to terminate the process (Figure 6).
The file upload form element is configured for POST method and “enctype”=”multipart/form-data” to handle file uploads. It includes an input type=”file” for selecting a file (input field named “0z3H8H8ato”) and an input type=”text” for providing a destination path or filename ( input field named “7KAjlfecWF”). If the HTML form for file upload is received from the TA, the file checks if the submission form field parameter named “7KAjlfecWF” (intended to be the file path or name) is not null or empty. The file retrieves the uploaded file through the “0z3H8H8atO” input using “HttpContext.Current[.]Request[.]Files[“Oz3H8H8ato”]”. If the file exists and has content (content length is greater than zero), the file saves the uploaded file using the path provided in the “7KAjlfecWF” field. Upon successful upload, the “InnerText” of an element named “Result” is set to “uploaded”, indicating the file has been saved. If an error occurs during the process, the file captures the exception and displays its details in “Result.InnerText” (Figure 6). The file displays server-side generated output or messages to the TA.
Screenshots
Figure 6 – Screenshot of the code snippet designed for handling various web-related operations, including setting and retrieving HTTP cookies, calculating a SHA512 hash of a request form value, starting an external cmd process and capturing its output, handling uploaded files from a request.
Figure 7 – Screenshot of the form that allows the TA to enter a password and submit it using a “Login” button, to enter a command, which can then be executed by clicking an “Execute” button, and a field for uploading files, featuring a file input (type=”file”) and a text input, both submitted using an “Upload” button.
This artifact is a malicious ASPX file with a “Page_Load” event handler that constructs and executes a command using PowerShell on the server (Figure 8). Upon execution, the file takes a Base64-encoded string from a form parameter named “p”. The Base64 encoded string is decoded and Exclusively-OR (XOR) decrypted using a hard-coded XOR key “68901a394a76dc5064fba96b862665ee596b1a1468bdc618157d7cca0130902e”. The output of the XOR decrypted bytes are converted to a Unicode Transformation Format-8 (UTF-8) string and then Base64 encoded. The Base64 encoded string is passed as an argument to the PowerShell process “powershell.exe” using the “-EncodedCommand flag”. The file redirects the standard output of the PowerShell process and reads it into a variable “o”, which is then written back to the HTTP response.
Screenshots
Figure 8 – Screenshot of the contents of the ASPX file.
This artifact is a malicious ASPX file with a “Page_Load” event handler that constructs and executes a command using PowerShell on the server (Figure 9). Upon execution, the file constructs a PowerShell command that decodes a Base64 string from the request form parameter “p”. The decoded string is decrypted using the XOR function with the hard-coded key “a859f0208777462899df67b3d81a7b8b”. The decrypted bytes (command) is executed using a PowerShell command. The standard output of the executed PowerShell command is converted to a UTF-8 string, then encrypted using the XOR function with the same hard-coded key. The encrypted bytes data is Base64 encoded before written to the HTTP response using “Response.Write”.
Screenshots
Figure 9 – Screenshot of the contents of the ASPX file.
CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.
Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).
Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.
CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://www.cisa.gov/forms/feedback
Document FAQ
What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.
What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.
Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.
Can I submit malware to CISA? Malware samples can be submitted via the methods below:
For larger files (over 100MB), please reach out to CISA for instructions.
CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.
