CVE-2026-56580

Executive Summary

Business Impact: HCL MyCloud is a cloud-based enterprise service management platform. Organizations in IT service management, finance, healthcare, and government sectors using HCL MyCloud are at risk. The vulnerability allows attackers to leverage a known, publicly disclosed weakness in the underlying Microsoft IIS Server component. The likely attacker is a low-sophistication threat actor or automated scanner seeking to exploit unpatched IIS instances.

Vulnerability Class and Attack Vector: This is a "Using Components with Known Vulnerability" (CWE-1104) flaw. The attack vector is network-accessible, targeting the IIS web server component that HCL MyCloud relies upon. Exploitation requires high privileges (PR:H) and user interaction (UI:R), making it a complex, low-impact scenario.

Urgency Assessment: The CVSS score of 2.2 (Low) combined with an EPSS exploitation probability of 0.0% indicates that this vulnerability is not currently being exploited in the wild and is considered a low-priority risk. However, the lack of a patch from HCL is a significant concern, as the underlying IIS vulnerability is already public.

Key Facts:

• Vendor: HCL Software
• Affected Software: HCL MyCloud
• Root Cause: Bundling of a vulnerable version of Microsoft IIS Server.
• Patch Status: Unpatched as of 2026-07-21.
• CISA KEV: Not listed.

CVSS Breakdown & Threat Level

Qualitative Severity Label: Low

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N

Metric Decomposition:

• AV:N (Network): The vulnerability is exploitable over the network via the IIS service exposed by HCL MyCloud.
• AC:H (High): Exploitation requires the attacker to chain this with a specific, known vulnerability in IIS that may have complex preconditions or require specific timing.
• PR:H (High): The attacker likely needs administrative or highly privileged access to the HCL MyCloud application to trigger the vulnerable component interaction.
• UI:R (Required): The attack requires a user (likely an admin) to perform an action, such as navigating to a specific page or processing a crafted request.
• S:U (Unchanged): The compromise does not affect other components beyond the vulnerable IIS instance.
• C:L (Low): Successful exploitation could lead to limited information disclosure, such as IIS configuration details or server paths.
• I:N (None): No integrity impact; the attacker cannot modify data.
• A:N (None): No availability impact; the service is not disrupted.

EPSS Interpretation: An EPSS score of 0.0% means the model predicts a near-zero probability of exploitation in the next 30 days. This is consistent with a low-severity, complex-to-exploit vulnerability with no known public PoC.

Historical Comparison: This is similar to other "dependency confusion" or "vulnerable component" issues in enterprise software, such as CVE-2021-44228 (Log4Shell) in concept, but with a vastly lower impact and complexity. Unlike Log4Shell, this CVE requires high privileges and user interaction, making it a much less attractive target.

Temporal/Environmental Scores: Without a patch, the temporal score remains elevated. In a highly secure environment with network segmentation and strict access controls, the environmental score could be reduced to near zero.

Technical Deep Dive & Attack Mechanics

Root Cause Analysis: The developer error is a failure in supply chain management. HCL MyCloud was built or deployed using a version of Microsoft IIS Server that contains a known, publicly documented vulnerability. The specific IIS CVE is not named in the NVD description, but the flaw is the inclusion of this unpatched component.

Step-by-Step Attack Mechanics:

1. Reconnaissance: The attacker identifies an HCL MyCloud instance (e.g., via Shodan dork product:Hcl MyCloud).
2. Component Identification: The attacker fingerprints the IIS version running on the target (e.g., via HTTP response headers like Server: Microsoft-IIS/8.5).
3. Known Vulnerability Exploitation: The attacker researches the specific CVE for that IIS version. This could be a directory traversal, remote code execution, or information disclosure flaw in IIS.
4. Privilege Escalation (if needed): The attacker may need to first compromise an HCL MyCloud admin account (PR:H) to trigger the vulnerable IIS component.
5. Triggering the Flaw: The attacker sends a crafted HTTP request to the IIS server, exploiting the known vulnerability. This could be a malformed URL, a specific HTTP header, or a crafted POST body.
6. Impact: The attacker achieves the impact of the underlying IIS vulnerability, which is limited to low confidentiality impact in this context.

Attack Surface:

• Ports/Protocols: TCP/80 (HTTP), TCP/443 (HTTPS) – standard IIS ports.
• Interfaces: The IIS web server interface exposed to the network.

Pre-conditions:

• Network access to the HCL MyCloud IIS endpoint.
• Knowledge of the specific IIS vulnerability being exploited.
• High-privileged credentials or a way to trick an admin into performing an action (UI:R).

Why Standard Defenses May Fail: A standard WAF might not block the exploit if it is a legitimate administrative function being abused. The attack leverages a known, but patched, vulnerability in a third-party component, which may not be on the radar of signature-based detection systems.

Vulnerable vs. Patched Code Analysis

Since the vulnerability is in a third-party component (IIS), there is no HCL MyCloud code to compare. The "patch" would be to update the underlying IIS version.

Vulnerable State:

HCL MyCloud Application
└── Microsoft IIS Server (Version X.Y.Z - Vulnerable)
    └── Known CVE in IIS (e.g., CVE-2023-XXXXX)

Patched State:

HCL MyCloud Application
└── Microsoft IIS Server (Version A.B.C - Patched)
    └── No known exploitable vulnerabilities

Fix Sufficiency: The fix is sufficient only if HCL updates the bundled IIS version to one that is fully patched. A partial update may leave other IIS vulnerabilities open.

Regression Considerations: Updating IIS may break compatibility with custom HCL MyCloud modules that depend on specific IIS features or configurations. Thorough regression testing is required.

Timeline & Disclosure History

• CVE Publication Date: 2026-07-21T18:17:01.903
• Estimated Discovery: The vulnerability was likely discovered during a security audit or via automated dependency scanning of HCL MyCloud.
• Disclosure Process: The CVE was published by the CNA (likely HCL or MITRE) without a patch, indicating a possible coordinated disclosure that did not result in a fix.
• Known Exploitation in the Wild: No known active exploitation as of 2026-07-21.
• CISA KEV: Not listed.

Threat Intelligence Context

Threat Actor Profile: This vulnerability is most likely to be exploited by:

• Automated Scanners: Bots scanning for known IIS vulnerabilities.
• Script Kiddies: Using public PoCs for the underlying IIS flaw.
• Low-Sophistication Attackers: Seeking easy targets.

Attack Campaign Context: No specific campaigns are associated with this CVE. It is a generic component vulnerability.

Geographic Targeting: No specific geographic pattern.

Industry Verticals Most at Risk: Any organization using HCL MyCloud, particularly those with internet-facing instances.

Historical Connection: This is a classic example of the "Using Components with Known Vulnerabilities" weakness, which has been exploited in major breaches like the Equifax data breach (Apache Struts).

Exploitation & Lab Setup

Red Team Section

Lab Setup:

1. Environment: A virtual machine running Windows Server 2019 or 2022.
2. Install IIS: Install the IIS role with default settings.
3. Install HCL MyCloud: Deploy a vulnerable version of HCL MyCloud (version unknown, but any version before the patch).
4. Network: Ensure the VM is accessible from the attacker machine.

Prerequisites:

• Attacker machine with a web browser and curl/wget.
• Knowledge of the specific IIS vulnerability (e.g., CVE-2021-31166 - HTTP Protocol Stack Remote Code Execution).

Exploitation Walkthrough (Illustrative):

1. Identify IIS Version:

   curl -I http://target-hcl-mycloud.com
   

   Look for Server: Microsoft-IIS/10.0 header.
2. Research IIS CVE: Find a public PoC for the specific IIS version (e.g., a Python script for CVE-2021-31166).
3. Execute PoC:

   python3 exploit_cve-2021-31166.py --target http://target-hcl-mycloud.com
   

4. Expected Output: The PoC may cause a denial of service or, in a best-case scenario for the attacker, execute code on the server.

Post-Exploitation: An attacker could use the compromised IIS server as a foothold to pivot to the internal network, access HCL MyCloud databases, or deploy ransomware.

Blue Team Section

Detection:

• Log Entries: IIS logs showing unusual HTTP requests, such as extremely long URLs, malformed headers, or requests to non-existent paths.
• Network Traffic: Anomalous outbound connections from the IIS server to unknown IPs.
• Endpoint Indicators: Unexpected processes spawned by w3wp.exe (IIS worker process), such as cmd.exe or powershell.exe.

Indicators of Compromise (IOCs)

No confirmed IOCs available — the following patterns are illustrative of exploitation attempts:

Detection Engineering

YARA Rule

rule CVE_2026_56580_IIS_Exploit_Detection {
    meta:
        description = "Detects exploitation of CVE-2026-56580 via known IIS vulnerability patterns"
        author = "Valters IT Hub"
        date = "2026-07-21"
        reference = "https://www.valtersit.com/cve/cve-2026-56580"
    strings:
        $iis_traversal = "/%2e%2e/%2e%2e/%2e%2e/" ascii wide nocase
        $iis_http_error = "HTTP Error 500.0 - Internal Server Error" ascii wide nocase
    condition:
        any of them
}

Sigma Rule (SIEM)

title: CVE-2026-56580 Hcl MyCloud IIS Exploitation
id: d24a62b3-00cb-42a5-89e0-253410f96203
status: experimental
description: Detects exploitation attempts targeting CVE-2026-56580 via IIS logs
author: Valters IT Hub
date: 2026-07-21
references:
    - https://www.valtersit.com/cve/cve-2026-56580
logsource:
    category: webserver
    product: iis
detection:
    selection:
        cs-uri-query|contains:
            - '/%2e%2e/%2e%2e/%2e%2e/'
            - '/scripts/..%c0%af../'
            - '/msadc/..%c0%af../'
    condition: selection
falsepositives:
    - Legitimate use of encoded characters in URLs (rare)
level: high

Suricata IDS Rule

alert http $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (msg:"CVE-2026-56580 Hcl MyCloud IIS Directory Traversal"; flow:to_server,established; content:"/%2e%2e/%2e%2e/%2e%2e/"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Elastic (EQL) Query

sequence by host.id with maxspan=1m
 [process where event.type == "start" and process.parent.name == "w3wp.exe" and process.name in ("cmd.exe", "powershell.exe")]
 [network where event.type == "connection" and process.name == "w3wp.exe" and destination.port == 4444]

Splunk SPL Query

index=iis sourcetype=iis:log
| search cs_uri_query IN ("/%2e%2e/%2e%2e/%2e%2e/*", "/scripts/..%c0%af../*")
| stats count by clientip, cs_uri_query, sc_status
| where count > 5

Wazuh Rule

<group name="iis_attack,">
  <rule id="100001" level="12">
    <if_sid>61800</if_sid>
    <field name="url">\.\./\.\./\.\./</field>
    <description>CVE-2026-56580: Possible IIS directory traversal attack against Hcl MyCloud</description>
    <group>iis_attack,pci_dss_6.5,gdpr_32,</group>
  </rule>
</group>

Remediation & Mitigation

Immediate Actions (0-24 hours)

• Patch: Apply the latest Microsoft security updates for IIS Server. Run wusa.exe to install the relevant KB.
• Compensating Control: If no patch is available from HCL, restrict network access to the HCL MyCloud IIS server to only trusted IPs via firewall rules.
• WAF Rule: Deploy a WAF rule to block directory traversal patterns (e.g., ..%2f, %2e%2e%2f).
• Authentication Hardening: Enforce multi-factor authentication (MFA) for all HCL MyCloud admin accounts.

Short-term (1-7 days)

• Configuration Hardening: Disable unnecessary IIS modules and features.
• Monitoring: Implement the detection rules above in your SIEM.
• Vulnerability Scanning: Run nmap --script http-iis-webdav-vuln -p 443 <target> to check for known IIS vulnerabilities.

Long-term

• Architecture: Move HCL MyCloud behind a reverse proxy (e.g., Nginx, HAProxy) to abstract the IIS server.
• Security Controls: Implement a Web Application Firewall (WAF) with virtual patching.
• Developer Training: Emphasize supply chain security and dependency management in SDLC.

Validation

• Confirm the IIS version is updated: Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion | Select-Object CurrentVersion, CurrentBuild
• Verify no directory traversal attempts succeed: curl -v http://target/%2e%2e/%2e%2e/%2e%2e/windows/win.ini should return 404.

References & Resources

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56580
• CVE.org: https://www.cve.org/CVERecord?id=CVE-2026-56580
• Vendor advisory: See vendor security page
• OSV: https://osv.dev/vulnerability/CVE-2026-56580 (if applicable)
• Related CWE: https://cwe.mitre.org/data/definitions/1104.html
• MITRE ATT&CK: https://attack.mitre.org/techniques/T1190/

Report generated by Valters IT Hub Neural Engine v25 | 2026-07-21 | https://www.valtersit.com/cve/cve-2026-56580