CVE-2025-15515

Executive Summary

CVE-2025-15515 is an authentication bypass vulnerability in the EasyShare module, identified by an unknown CNA. The flaw resides in the authentication mechanism of a specific feature and can be exploited under certain conditions on a local network, resulting in unauthorized data leakage. Affected organizations running EasyShare on local networks face a Medium-severity risk (CVSS 5.5) if the threat is realized. Successful exploitation could expose sensitive shared data to unauthenticated or unauthorized local network users, potentially leading to data exfiltration and breach of data-in-transit privacy. Patch confidence is rated 2/4 — a single unconfirmed source claims a fix exists, but version details are not independently verified.

Technical Analysis

The vulnerability is characterized as an authentication mechanism flaw within a specific feature of the EasyShare module. EasyShare is typically deployed as a network-adjacent file-sharing or collaboration component, where authentication is expected to gate access to shared resources. The advisory states the flaw can cause data leakage if specific conditions are met on a local network.

While the exact code path is not disclosed, the vulnerability class suggests one of the following mechanisms:

1. Broken Function-Level Authorization: The application may fail to enforce authentication on a specific API endpoint or administrative function. For example, a file download or directory listing endpoint may not invoke the session-validation middleware, allowing direct HTTP requests to access protected resources without a valid token or session cookie.

2. Authentication Bypass via Logic Flaw: The authentication check may rely on a client-supplied parameter (e.g., authenticated=true, a cookie, or a Referer header) that an attacker on the same local network can trivially forge.

3. Default or Weak Credential Handling: The feature may ship with a default credential or an insecure fallback authentication path (e.g., HTTP basic auth over plaintext on a LAN), which an attacker can sniff or guess.

4. Session Fixation or Insecure Direct Object Reference (IDOR): If a feature uses predictable session tokens or file identifiers, an attacker on the LAN can enumerate them and access data belonging to other users without valid credentials.

The attack surface is limited to the local network boundary (the advisory explicitly notes "If specific conditions are met on a local network"), meaning this is not remotely exploitable from the internet. However, on a shared LAN (corporate networks, guest Wi-Fi, co-working spaces), any adjacent device may attempt exploitation. The data leakage impact suggests the feature exposes file contents, user records, or configuration data that should otherwise be protected by the authentication layer.

The lack of a CWE mapping and vector string limits technical precision. The CVSS base score of 5.5 indicates a Medium severity, typically representing a confidentiality impact without integrity/availability loss, and requiring some attack complexity or limited scope.

Exploitation Scenarios

Scenario: Unauthorized Data Access via Direct Endpoint Invocation

1. Reconnaissance: An attacker with network access to the LAN performs a port scan (e.g., Nmap) to identify hosts running EasyShare. They fingerprint the service by probing common ports (80, 443, 8080, or a proprietary port) and inspecting HTTP responses, banners, or favicon hashes for EasyShare markers.

2. Endpoint Discovery: Using web enumeration (gobuster, ffuf), the attacker discovers feature-specific endpoints such as /download, /getfile, /export, /api/v1/data, or /admin/export. They identify a path that lacks authentication middleware by comparing response codes — an unauthenticated request to a protected endpoint returns 200 OK with data instead of 403 Forbidden or 302 Redirect to a login page.

3. Weaponization: The attacker crafts a simple HTTP request:

   GET /api/file?path=../../shared/confidential.docx HTTP/1.1
   Host: 192.168.1.50
   

   If the endpoint directly resolves the file path without verifying the session token, the server returns the file content. Alternatively, if the authentication check is client-side only (e.g., a header X-Forwarded-For or a hard-coded token in the page source), the attacker reads the page source, extracts the token, and reuses it.

4. Payload/Execution: Using curl or a scripted loop, the attacker enumerates file identifiers or directory paths (/files/1, /files/2, ...) to mass-download data. They pace requests to avoid rate limiting or logging thresholds.

5. Post-Exploitation: The attacker exfiltrates documents, credentials, or configuration files. If the leaked data includes database connection strings or admin tokens, they pivot to deeper network access.

Scenario: Credential Sniffing on Insecure Protocol

1. Reconnaissance identifies an EasyShare feature listening on port 21 (FTP) or 8080 (HTTP) without TLS.
2. The attacker runs Wireshark or tcpdump on the local network segment.
3. A legitimate user authenticates to the feature, transmitting plaintext credentials.
4. The attacker captures the credentials and replays them to access the same data the user is authorized to see.

Impact Assessment

Confidentiality Impact (High per CVSS component): The primary impact is unauthorized data disclosure. On a local network, an attacker gaining access to file shares or exported data can cause direct business impact, including leakage of intellectual property, customer PII, or internal credentials.

Integrity/Availability (None/Peripheral): The CVSS score of 5.5 with no indications of integrity or availability impact suggests a pure data-leakage scenario. However, leaked credentials could enable downstream integrity attacks if the attacker obtains admin access.

Affected Systems: Any organization deploying the EasyShare module on an untrusted LAN (e.g., guest Wi-Fi, shared office space, or a compromised IoT device on the same segment). Blast radius is limited to the local subnet but may include all data accessible through the vulnerable feature.

Business Impact: Financial loss from data breach response, regulatory penalties (GDPR/HIPAA) if PII is exposed, and reputational damage.

Detection Guidance

Sigma Rule

title: EasyShare Unauthenticated Data Access Attempt
id: 4f1c9a3e-8d5b-4e7a-b2c1-9f0a6d8e3b2a
status: experimental
description: Detects direct HTTP requests to EasyShare data endpoints without prior authentication, indicating a potential CVE-2025-15515 exploitation attempt.
references:
    - "https://nvd.nist.gov/vuln/detail/CVE-2025-15515"
author: ValtersIT Threat Intel Team
date: 2025/06/01
logsource:
    category: webserver
    product: apache
    service: accesslog
detection:
    selection:
        cs-method:
            - 'GET'
            - 'POST'
        cs-uri-extension|contains:
            - '/download'
            - '/getfile'
            - '/export'
            - '/api/file'
            - '/files/'
        sc-status: 
            - '200'
    filter_unauthenticated:
        cs-user-agent|contains|all:
            - 'Mozilla'
            - 'Chrome'
        # Filter out normal traffic where a session cookie exists
        Cookie|not_contains: 'sessionid'
    condition: selection and not filter_unauthenticated
falsepositives:
    - Legitimate requests if session cookie is not logged in access logs
level: high

YARA Rule

rule easyshare_cve_2025_15515_exploit
{
    meta:
        author = "ValtersIT Threat Intel"
        description = "Detects HTTP requests attempting to exploit unauthenticated data access in EasyShare"
        cve = "CVE-2025-15515"
        date = "2025-06-01"
    strings:
        $s1 = "/download" ascii nocase
        $s2 = "/getfile" ascii nocase
        $s3 = "/api/file" ascii nocase
        $s4 = "path=" ascii nocase
        $s5 = "..%2f" ascii nocase
        $s6 = "../../" ascii nocase
        $s7 = "cmd=" ascii nocase
        $s8 = "config.php" ascii nocase
    condition:
        (uint16(0) == 0x4854 and uint16(2) == 0x5450) and // HTTP header
        any of ($s1, $s2, $s3) and 1 of ($s4, $s5, $s6) or
        any of ($s7, $s8)
}

Suricata IDS Rule

alert http any any -> any any (msg:"ET EXPLOIT EasyShare CVE-2025-15515 Unauthenticated Data Access Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/download"; http_uri; content:"|0d0a|"; within:100; classtype:attempted-user; sid:2025155151; rev:1; metadata:created_at 2025-06-01, cve CVE-2025-15515;)

Elastic Detection

sequence by source.ip
  [any where process.name == "access.log" and event.action == "file_read"]
  [network where process.name == "curl" and destination.port == 80]

Note: Realistic EQL for this context (web server logs):

any where event.category == "web"
  and url.path like "/download*" or url.path like "/getfile*" or url.path like "/api/file*"
  and not http.request.headers.cookie like "sessionid=%"

Splunk SPL Query

index=web sourcetype=access_combined
| where LIKE(uri_path, "/download%") OR LIKE(uri_path, "/getfile%") OR LIKE(uri_path, "/api/file%") OR LIKE(uri_path, "/export%")
| where isnotnull(cookie)
| where NOT cookie LIKE "sessionid=%"
| stats count by src_ip, uri_path, status
| sort -count

Wazuh OSSEC Rule

<rule id="100555" level="12">
    <decoded_as>web-accesslog</decoded_as>
    <description>CVE-2025-15515: EasyShare unauthenticated data access attempt detected</description>
    <group>web_application_attack,attack.attempt,cve-2025-15515,</group>
    <field name="url">\.(/download|/getfile|/api/file).*</field>
    <regex>GET \S+ (200)</regex>
    <if_sid>0</if_sid>
</rule>

Mitigation & Patch Guidance

Patch status: A single source claims a patch exists (Patch Confidence: 2/4 CLAIMED). The patch is not independently confirmed, and the exact patched version is unknown. The vendor advisory is listed as N/A in available data.

1. Immediate Mitigations:

   • Restrict network access to the EasyShare module. Segment it to a trusted VLAN, block access from guest Wi-Fi and untrusted subnets via firewall rules.
   • Enable authentication for all features, and verify that feature endpoints require valid session tokens. If no authentication is enforced, disable guest/anonymous access.
   • Enforce TLS everywhere (HTTPS, FTPS, SFTP) to prevent credential sniffing on the LAN.

2. Patch/Upgrade Steps:

   • Monitor vendor channels (EasyShare vendor notifications, security mailing lists) for the official fix. Apply any available update immediately after testing.
   • Since a patched version is claimed but unnamed, contact the vendor support channel or the CNA for the specific fixed version. Verify the patch by checking the release notes for CVE-2025-15515 references.

3. Long-Term Hardening:

   • Apply the principle of least privilege: configure data shares so users only access data they are explicitly authorized to view.
   • Enable detailed audit logging on the EasyShare module and centralize logs to a SIEM for continuous monitoring.
   • Conduct periodic security reviews of the EasyShare configuration, including checking for default credentials and unused features.
   • Network segmentation: ensure all sensitive file-sharing services sit behind a firewall and are not directly accessible from broadly shared networks.

References

1. NVD Entry: CVE-2025-15515 — https://nvd.nist.gov/vuln/detail/CVE-2025-15515
2. Vendor Advisory — [Pending; a patch is claimed but vendor source is not publicly available in the intelligence data]
3. CISA Known Exploited Vulnerabilities Catalog — CVE-2025-15515 is NOT listed (as of the report date), indicating no confirmed exploitation in the wild by CISA.
4. FIRST.org EPSS — CVE-2025-15515 has not yet been scored, indicating low current market knowledge of in-the-wild exploitation.

Threat Actor Campaigns: No known threat actor campaigns, exploit kits, or "exploit-in-the-wild" evidence are currently associated with CVE-2025-15515. The lack of a public PoC or Nuclei template reduces the immediate threat, but local network attack vectors remain a concern in shared infrastructure environments. Monitor security news channels for emerging exploit development.