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SonicWall SMA1000 CVE-2026-102255: SSRF Attack Attempts Targeting Internal CouchDB

#security #threatintel

1. Basic Information

2. Executive Summary

Attackers sent crafted OPTIONS requests to Appliance WorkPlace to reach localhost CouchDB and the _rewrite function via SSRF. While Previdian's honeypot observed these attempts, successful system compromise remains unconfirmed.

3. Attack Flow

Observed SSRF Attempts

  1. An attacker sends a crafted OPTIONS request to the internet-facing Appliance WorkPlace Extraweb.
  2. The SSRF request attempts to force the appliance itself to send a request to CouchDB at 127.0.0.1:5984. Public information has not confirmed whether internal forwarding or CouchDB operations succeeded.
  3. The payload attempts to traverse into a CouchDB design document and invoke its _rewrite function, using HTTP Basic authentication with the credentials admin:admin.
  4. If internal operations succeed, it could lead to unauthorized actions on the appliance, but public sources have not confirmed success.

4. Attacker Position and Execution Context

  • A remote unauthenticated attacker with network reachability to the WorkPlace interface.

5. Victim and Administrator Perspective

  • Users: There may be no noticeable changes on the standard VPN screen; disruptions or re-authentication prompts alone do not confirm a compromise.
  • Administrators: Indicators may appear as anomalous OPTIONS requests on Extraweb, localhost CouchDB access, _rewrite calls, or changes in configuration and service state.

6. Conditions for Success and Failure

Success Conditions

  • Appliance WorkPlace is reachable on a vulnerable version of SMA1000.
  • The crafted request is forwarded to the internal CouchDB, and the targeted operation is accepted.

Failure Conditions and Mitigations

  • Update to the fixed hotfix to close the SSRF vector.
  • Minimize internet exposure of WorkPlace and management interfaces, using WAFs and ACLs to restrict abnormal methods and sources.

7. Impact of Successful Exploitation

  • Pre-authentication access and unauthorized operations on internal appliance functions.
  • Potential configuration tampering, credential access, or subsequent compromise of the internal network using the remote access gateway as a foothold.
  • Additional risks of RCE, path traversal, or stored XSS if other vulnerabilities in the concurrent notice remain unpatched.

8. Observable Logs

The following are candidates for internal investigation and do not represent a confirmed list of observations for this specific incident.

  • Email: No email-based initial vectors specific to this issue have been confirmed.
  • Proxy / SWG / DNS: Check for OPTIONS requests targeting WorkPlace/Extraweb, abnormal paths, Authorization headers, and WAF alerts.
  • Endpoint / EDR: Monitor appliance processes, CouchDB audit logs, configuration files, service restarts, and unexpected file changes.
  • Identity / IdP: Look for unusual logins, session creation, or credential changes for SMA administrators and VPN accounts.
  • SaaS / Cloud: Check for configuration changes and account operations from MSSP management consoles or central management.
  • Network: External sensors should check for requests to WorkPlace, internal network scans, and unusual egress. Internal forwarding to 127.0.0.1:5984 can be verified via available loopback captures or application/CouchDB logs on the appliance.

9. Determining Attack Success

Confirmed in Public Information

  • Attack Attempts Observed (Success Unconfirmed): Crafted requests consistent with CVE-2026-102255 were observed on Previdian's honeypot network, but successful system compromise has not been established.

Internal Evaluation Criteria

  • Correlate requests, responses, processes, authentication, data access, and outbound traffic chronologically to distinguish between attack attempts and success.
  • Do not conclude success based solely on HTTP status codes or a single alert when not supported by public data.

10. Investigation Playbook

  • Starting Point: Begin with OPTIONS requests to WorkPlace, CVE-2026-102255 alerts, and the SonicWall notice.
  • Initial Review: Verify the model, firmware/hotfix level, WorkPlace exposure, source IP, and request/response for the relevant timestamp.
  • Endpoint/Server Investigation: Preserve evidence related to CouchDB, Extraweb, configurations, file integrity, processes, crashes, and reboots.
  • Authentication/Cloud Investigation: Review administrator and VPN accounts, sessions, certificates, MFA, and credential changes.
  • Subsequent Actions: Track internal scanning, credential access, webshells/additional files, tunnels, and external transmissions.
  • Containment: Restrict WorkPlace reachability, update to the fixed hotfix, isolate the appliance if compromise indicators are present, and rotate credentials.
  • Classification: Distinguish between attack attempts, initial execution, successful authentication, data theft, and subsequent compromise. Do not treat unverified outcomes as confirmed based on assumptions alone.

11. Defense and Detection Ideas

  • Single Events: Detect abnormal OPTIONS requests to Extraweb, paths targeting localhost CouchDB, and _rewrite usage. If Authorization headers are captured, inspect the Base64-decoded result of Basic authentication values.
  • Chronological Correlation: Correlate external OPTIONS requests -> localhost CouchDB -> configuration changes/service anomalies -> internal scanning and authentication chronologically.
  • Threat Hunting: Search historical logs for abnormal methods against WorkPlace, 127.0.0.1:5984, and _rewrite. For Basic authentication, check requests where the decoded credential is admin:admin. Searching only for plaintext strings or standard access logs may cause items to be missed.
  • Log Limitations: Network logs alone cannot determine success if TLS termination and internal appliance requests are not visible.
  • Priority Mitigations: Apply emergency patches, restrict WorkPlace exposure, preserve appliance audit data, implement WAF rules, and rotate management credentials.

12. Facts / Inference / Hypothesis

Facts

  • Previdian's honeypot network observed attack attempts consistent with CVE-2026-102255.
  • The observed request used the OPTIONS method against WorkPlace Extraweb and attempted to access CouchDB at 127.0.0.1:5984, traverse into a design document, and invoke _rewrite. It supplied an HTTP Basic Authorization header whose decoded credentials were admin:admin.
  • Previdian has not confirmed whether the observed attempts successfully compromised any systems.
  • SonicWall rated CVE-2026-102255 as a CVSS 10.0 SSRF vulnerability, explaining that a remote unauthenticated attacker can force the appliance to send proxy requests and reach internal functions for unauthorized operations.
  • Affected SMA1000 models are 6210, 7210, and 8200v, with affected hotfix levels of 12.4.3-03526 and earlier, or 12.5.0-02952 and earlier. SMA 100 Series appliances and SSL-VPN on SonicWall firewalls are not affected.
  • Fixed versions are 12.4.3-03670 and later, or 12.5.0-03082 and later. SonicWall's notice stated at the time of update that there was no evidence of active exploitation, differing from the timestamp and scope of honeypot observations.
  • Shadowserver tracks over 400 internet-exposed SMA1000 devices, but the breakdown of honeypots, patched systems, and vulnerable configurations remains unknown.

Inference

  • While the vendor has not confirmed active exploitation, third-party honeypots have observed exploit requests. Therefore, SOCs should treat this as "attack attempts observed, success unconfirmed."
  • Because localhost CouchDB requests are not directly visible from the outside, determining success requires combining Extraweb access logs with internal appliance communications and audit evidence.

Hypothesis

No additional hypotheses. Unconfirmed items are listed in "14. Open Questions and Further Investigation."

13. MITRE ATT&CK Mapping

ID Technique Confidence Basis
T1190 Exploit Public-Facing Application high Pre-authentication SSRF requests targeting the internet-facing WorkPlace interface have been observed.

14. Open Questions and Further Investigation

  • HTTP responses to the observed requests, the success or failure of CouchDB operations, and whether configurations or data were modified.
  • The attacker's identity, campaign scale, and whether the same actor progressed to subsequent RCE or credential theft.
  • Among the over 400 publicly exposed devices, the exact count of affected versions and unpatched systems.

15. Impact on SOCs and Organizations

As an SMA1000 is a remote access gateway, a compromise breaches the boundary to internal applications. Organizations should immediately verify their WorkPlace exposure and hotfix levels, and retrospectively investigate pre- and post-update OPTIONS requests, localhost:5984, _rewrite, decoded credentials from captured Basic authentication headers, and appliance configuration changes.

16. Summary by Role

  • For SOCs: Correlate crafted OPTIONS requests to WorkPlace, CouchDB localhost access, _rewrite, configuration changes, and subsequent authentication to distinguish between attempts and successful compromises.
  • For Administrators: Update to version 12.4.3-03670 or later (or 12.5.0-03082 and later), and minimize WorkPlace exposure and management interface accessibility.
  • For Users: General user action is not required. Report any VPN connection anomalies or unrequested re-authentication prompts to administrators.

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