CVE-2020-10510

Executive Summary

CVE-2020-10508 is a Broken Access Control vulnerability in Sunnet eHRD, a human training and development management system. Authenticated attackers can exploit a specific URL to access unauthorized functionality and data, potentially exposing sensitive employee training records, personal data, and administrative functions. The vulnerability carries a CVSS score of 8.1, reflecting high confidentiality and integrity impact, and affects all versions prior to version 10.

Technical Analysis

The vulnerability resides in Sunnet eHRD, an enterprise human resource training and development management platform. The flaw is classified as Broken Access Control (CWE-284), which occurs when an application fails to enforce proper authorization checks for authenticated users. While the application correctly authenticates users at the login stage, it fails to perform subsequent authorization validation on every protected resource or function call.

The NVD description indicates that "after login, attackers can use a specific URL, access unauthorized functionality and data." This pattern is characteristic of Insecure Direct Object Reference (IDOR) or missing function-level access control. In such implementations, the application verifies that a user has valid credentials (authentication) but fails to verify whether that user has the appropriate privilege level to access the requested resource (authorization). This is a common flaw in web applications where HTTP request parameters, URL paths, or resource identifiers are used directly to determine which data or functionality is returned, without adequate server-side permission checks.

The attack requires authenticated access to the application, meaning the attacker must have at least a low-privileged account. Once authenticated, the attacker can manipulate the URL or request parameters to target administrative endpoints, view other users' data, or invoke privileged functions. The specific endpoint or parameter names are not disclosed in the public advisory.

The CVSS vector indicates the attack vector is network-based (AV:N) with low attack complexity (AC:L), requires low privileges (PR:L), and has no user interaction (UI:N). The scope is unchanged (S:U), but both confidentiality and integrity impact are rated high (C:H/I:H), indicating the attacker can read sensitive data and potentially modify or corrupt application data. Availability is unaffected (A:N), suggesting the flaw does not lead to denial of service.

No CWE identifier was provided in the CVE data; however, the vulnerability class — Broken Access Control — maps directly to CWE-284, with possible sub-classifications into CWE-639 (Authorization Bypass Through User-Controlled Key) or CWE-862 (Missing Authorization), depending on the specific implementation details. The NVD description does not provide enough information to distinguish between these sub-classes.

Exploitation Scenarios

The following attack chain is inferred from the vulnerability description. As no public PoC or exploit code is available, specific URL patterns and request structures cannot be confirmed:

Step 1 — Reconnaissance/Target Identification: The attacker identifies an exposed Sunnet eHRD instance, typically via Shodan or Google dorks targeting the application's web interface. The attacker then needs to obtain valid credentials, either through credential stuffing, phishing, weak-password guessing, or by purchasing credentials from breach databases. The attacker can also create a low-privileged account if self-registration is enabled on the platform.

Step 2 — Triggering the Access Control Flaw: After successful login, the attacker systematically enumerates application URLs, and modifies request parameters such as user IDs, record IDs, or role identifiers in the URL path. The application fails to validate whether the authenticated session has authorization to access the target resource. The attacker can also attempt to access administrative URLs directly by guessing or discovering common paths (e.g., admin panels, user management interfaces) or by leveraging directory traversal techniques to map the application's functionality.

Step 3 — Payload/Execution Method: The attack class is Broken Access Control — no payload injection is required. The attacker directly modifies HTTP GET/POST requests targeting URLs that expose sensitive functionality. For example, if the application exposes user records via a URL parameter — commonly structured as /user/ or similar record identifiers — the attacker systematically iterates through numeric IDs to harvest data belonging to other users or administrative accounts. The attack succeeds because the application does not enforce server-side authorization checks on these protected endpoints.

Step 4 — Post-Exploitation Impact: The attacker gains access to unauthorized functionality and data. This can include viewing or exfiltrating sensitive employee training records, personal identification information (PII), salary data, performance reviews, and administrative credentials. The attacker may also invoke privileged functions such as creating user accounts, modifying training records, or altering application configuration, thus causing data integrity loss. The attacker can escalate privileges to administrative level, facilitate lateral movement within the enterprise environment, and potentially pivot to other internal systems.

Impact Assessment

The vulnerability poses a severe risk to organizations deploying Sunnet eHRD. The CVSS score of 8.1 (High severity) underscores the significance of the flaw. Confidentiality impact is rated High, meaning the attacker can gain full access to sensitive data managed by the system, including employee PII, training records, performance evaluations, and potentially salary information. Integrity impact is also rated High, allowing the attacker to modify or delete records, potentially corrupting training and HR data critical for compliance and audit purposes.

The attack surface is limited to authenticated users, which may seem to reduce the threat; however, the low-privilege requirement (PR:L) means that any employee or external contractor with a minimal account can exploit the vulnerability. In enterprise settings where eHRD systems may have large user bases, the exposure is substantial. The blast radius extends beyond the eHRD data itself: compromised HR systems often hold data that attackers use for targeted social engineering, identity theft, and further lateral movement into related HRMS and payroll infrastructure. The EPSS score of 0.01058 (61.4th percentile) indicates moderate exploitation likelihood in the wild.

Because the vulnerability is unpatched in older versions and the product's fix requires either manual update to version 10 or direct contact with the vendor, organizations running unsupported legacy versions face prolonged exposure. No workarounds or temporary mitigations were provided by the vendor.

Detection Guidance

Given the absence of specific URL structures and payload signatures, detection guidance focuses on baseline anomalies rather than exact signatures. The following detection rules are generic and should be tested and tuned to match the organization's specific eHRD application and network environment.

Sigma Rule

title: Sunnet eHRD - Suspicious Access to Admin/User Management URLs
id: 15a2f3c4-8b6d-4e7a-9f0c-2d3e4f5a6b7c
status: experimental
description: Detects authenticated users accessing potentially unauthorized admin or user-management URLs on Sunnet eHRD, indicating possible Broken Access Control exploitation (CVE-2020-10510).
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2020-10510
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2020-10510
logsource:
    category: webserver
    product: apache
    service: accesslog
detection:
    selection:
        cs-method:
            - 'GET'
            - 'POST'
        cs-uri-query|contains:
            - 'admin'
            - 'user'
            - 'role'
            - 'permission'
        cs-username: '*'
    condition: selection
    timeframe: 1h
falsepositives:
    - Legitimate administrative operations by authorized users
    - URL patterns may vary across deployments
level: medium

YARA Rule

rule Sunnet_eHRD_Broken_Access_Control_CVE_2020_10510
{
    meta:
        author = "ValterSecurity Threat Intel"
        description = "Detects malicious requests targeting Sunnet eHRD applications attempting to access unauthorized resources"
        cve = "CVE-2020-10510"
        date = "2024-01-01"
        version = "1.0"

    strings:
        $s1 = "eHRD" nocase
        $s2 = "user" nocase
        $s3 = "admin" nocase
        $s4 = "config" nocase
        $s5 = "profile" nocase
        $s6 = ".jsp" nocase
        $s7 = ".do" nocase
        $s8 = ".action" nocase

    condition:
        uint16(0) == 0x0D0A and // Check for HTTP protocol
        any of ($s1, $s6, $s7, $s8) and
        2 of ($s2, $s3, $s4, $s5)
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"SUNNET eHRD - Broken Access Control Attempt (CVE-2020-10510)"; flow:established,to_server; content:"GET"; http_method; content:!".css"; http_uri; pcre:"/(admin|user|role|permission|config|profile)/i"; classtype:attempted-admin; reference:cve,2020-10510; sid:20200510; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=10m
  [ authentication where event.action == "login" and user.name != null and process.name == "httpd" ]
  [ http where http.request.method == "GET" and url.path in ("/admin", "/user", "/config", "/profile") or url.path like "*admin*" or url.path like "*config*" ]
  [ file where event.action == "modification" and not (user.name == "root" or user.name == "SYSTEM") and file.extension in ("xls", "csv", "json", "pdf") ]

Splunk SPL Query

index=web sourcetype=access_combined_wc3
| table _time src_ip http_method http_uri http_user_status user cs_username
| where http_method IN ("GET","POST")
| where http_uri LIKE "%admin%" OR http_uri LIKE "%user%" OR http_uri LIKE "%config%" OR http_uri LIKE "%profile%"
| stats count by src_ip, http_uri, user, cs_username
| sort - count
| where count > 10
| appendpipe [
    | eval severity="HIGH"
    | eval cve="CVE-2020-10510"
    | eval description="Possible Broken Access Control attempts on Sunnet eHRD"
  ]

Wazuh OSSEC Rule

<group name="sunnet_ehrd, attacks,">
  <rule id="202051" level="12">
    <if_sid>31100</if_sid>
    <url>\.(jsp|do|action)$</url>
    <regex>.*\/(admin|user|config|role|permission|profile).*</regex>
    <description>Sunnet eHRD - Possible unauthorized access to restricted URL (CVE-2020-10510)</description>
    <group>access_control_broken,</group>
    <mitre>
      <id>T1190</id>
    </mitre>
    <options>no_full_log</options>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence Assessment: The vendor claims a patch is available, but this is a single-source claim not independently confirmed. Caution is advised if considering the application fully remediated based solely on this claim.

1) Immediate Mitigations:

• Restrict access to the Sunnet eHRD web interface to trusted IP ranges via firewall or reverse proxy ACLs
• Implement additional application-layer authentication (e.g., MFA) to reduce the risk of compromised low-privilege credentials
• Deploy a WAF with rules to block access to administrative URL patterns from non-administrative IPs
• Disable self-registration features if enabled
• Conduct a review of all user accounts and remove dormant or unofficial accounts

2) Patch/Upgrade Steps:

• Contact Sunnet directly at their official support channel to request the security patch for CVE-2020-10510
• Upgrade to eHRD version 10 or latest available version
• Verify the patch integrity by comparing checksums against official vendor documentation
• After applying the fix, perform regression testing on all critical workflows: user management, training records access, and reporting functions
• Confirm patch installation by verifying version number in the application's about page or configuration file

3) Long-Term Hardening:

• Replace Sunnet eHRD with a maintained alternative if the vendor discontinues support for older versions
• Establish a vulnerability management program ensuring timely patching of HR applications
• Implement regular security testing (penetration testing and SAST) throughout the application lifecycle
• Apply principle of least privilege to all user accounts in the HR system
• Enable comprehensive logging and audit trail functionality on the eHRD platform
• Segment the HR application into a dedicated network zone isolated from corporate data
• Mandate background verification and periodic re-certification of user access rights

References

1. NVD Entry for CVE-2020-10510: https://nvd.nist.gov/vuln/detail/CVE-2020-10510
2. CVE.org Record: https://cve.org/CVERecord?id=CVE-2020-10510
3. CISA Known Exploited Vulnerabilities Catalog (Not Listed — as of this report date): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
4. FIRST EPSS Score for CVE-2020-10510: https://www.first.org/epss/search?cve=CVE-2020-10510
5. Vendor Contact Portal — Sunnet: (via official product support channel)

Threat Actor Activity: As of this report date, CVE-2020-10510 has not been observed in active exploitation campaigns, and no public exploit code or PoC exists. The vulnerability remains a documented risk for entities running unpatched versions of Sunnet eHRD, and the moderate EPSS score suggests the possibility of future adoption by lower-sophistication threat actors.