CVE-2016-7836
SKYSEA Client View Improper Authentication Vulnerability
Description
CVE-2016-7836 is a critical remote code execution vulnerability (CVSS 9.8) in SKYSEA Client View version 11.221.03 and earlier, a widely deployed endpoint management and IT asset monitoring product. The vulnerability stems from improper authentication (CWE-287) in the processing of TCP connections with the management console program, allowing an unauthenticated remote attacker to execute arbitrary code on affected systems. CISA has included this vulnerability in the Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of November 4, 2025, and its EPSS score of 35.34% (97.0th percentile) indicates an extremely high probability of active exploitation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| skygroup | skysea client view | <= 11.221.03 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://www.securityfocus.com/bid/95062(Third Party Advisory, VDB Entry)
- http://www.skyseaclientview.net/news/161221/(Vendor Advisory)
- https://jvn.jp/en/jp/JVN84995847/index.html(Third Party Advisory, VDB Entry)
- https://www.skygroup.jp/security-info/170308.html(Exploit, Technical Description, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-7836(US Government Resource)
Weakness Type
CWE-287: Improper Authentication
CWE-287 occurs when software does not sufficiently verify that a user or system has proven its identity before granting access to protected resources or functionality. In CVE-2016-7836, the SKYSEA Client View application fails to properly authenticate TCP connections from the management console program, allowing an attacker to bypass authentication entirely and execute commands as if they were a trusted management console. This class of weakness is particularly dangerous in network-facing management tools because it allows unauthenticated remote access to systems that are designed to have extensive control over endpoints.
Impact Analysis
The business impact of CVE-2016-7836 is severe. SKYSEA Client View is an endpoint management solution, meaning a compromise of this software could give an attacker control over all managed endpoints in an organization. Confidentiality is fully compromised because the attacker gains the ability to execute arbitrary code on the SKYSEA server, which typically stores or has access to endpoint inventory data, configuration details, and potentially credentials used for remote management. Integrity faces maximum impact since arbitrary code execution allows the attacker to modify system configurations, deploy malicious software to managed endpoints, alter monitoring data, and manipulate the management infrastructure itself. Availability is equally threatened as the attacker could disable the management platform, disrupt endpoint monitoring, or use the access to deploy destructive payloads across all managed systems.
With an EPSS score of 35.34% (97.0th percentile), this vulnerability is among the top 3% most likely to be exploited of all known CVEs. The network-accessible attack vector (AV:N) with no authentication required (PR:N) and no user interaction needed (UI:N) makes this an ideal target for automated exploitation. While the ransomware association is listed as "Unknown," the ability to execute code on a centralized management platform creates an extremely efficient distribution point for ransomware across all managed endpoints. Organizations still running vulnerable versions of SKYSEA Client View face existential risk to their IT infrastructure.
Exploit Maturity
CVE-2016-7836 demonstrates a very mature exploitation landscape. CISA has included it in the Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of November 4, 2025, confirming active exploitation. The EPSS score of 35.34% (97.0th percentile) is exceptionally high, placing this vulnerability among the most exploited CVEs globally.
A detailed technical description and exploit information has been published by SKYGROUP, providing technical details about the vulnerability. Additionally, vulnerability database entries at SecurityFocus (BID 95062) and JVN (JVN#84995847) provide further context. The combination of a nearly decade-old vulnerability, public exploit information, and a perfect network attack surface (CVSS 9.8) makes this an extremely attractive target. The ransomware exploitation status is listed as "Unknown," but the centralized management nature of SKYSEA Client View makes it a high-value target for threat actors seeking wide-scale deployment of malicious payloads.
Remediation
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Upgrade SKYSEA Client View to a patched version immediately. Update all SKYSEA Client View installations beyond version 11.221.03 to a version that addresses the authentication bypass vulnerability. Refer to the official vendor advisory for the specific patched version and download instructions.
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Restrict network access to the SKYSEA management console port. Until patching is complete, implement firewall rules to strictly limit TCP access to the SKYSEA Client View management console interface. Only allow connections from authorized management workstations on trusted network segments, blocking all other inbound traffic to the vulnerable service.
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Audit systems for signs of compromise. Given the long-standing nature of this vulnerability (disclosed in 2016) and its confirmed exploitation, perform a thorough investigation of all systems running SKYSEA Client View. Check for unauthorized code execution, unexpected processes, new user accounts, modified configurations, and any indicators of compromise on both the management server and managed endpoints.
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Implement network segmentation for management infrastructure. Place SKYSEA Client View servers and management consoles in a dedicated, segmented network zone with strict access controls. This limits the blast radius if the management platform is compromised and reduces the attack surface for network-based exploitation.
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Evaluate alternative endpoint management solutions. Given the critical severity and the age of this vulnerability, assess whether continuing to use SKYSEA Client View is appropriate for your organization's risk profile. If the vendor has not provided timely and comprehensive security updates, consider migrating to a more actively maintained endpoint management platform.
Technical Details
The CVSS v3.1 vector for CVE-2016-7836 is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, resulting in a critical base score of 9.8. Attack Vector (AV:N) indicates the vulnerability is exploitable remotely over the network, requiring no local or physical access. Attack Complexity (AC:L) means exploitation is straightforward with no special conditions. Privileges Required (PR:N) confirms that no authentication whatsoever is needed—the attacker can exploit this as a completely unauthenticated remote user. User Interaction (UI:N) specifies that no victim action is required. Scope (S:U) indicates the impact stays within the vulnerable component's authority. All three impact metrics—Confidentiality (C:H), Integrity (I:H), and Availability (A:H)—are rated High, reflecting complete system compromise.
The vulnerability exists in the authentication handling of TCP connections between the SKYSEA Client View managed clients/agents and the management console program. SKYSEA Client View uses a TCP-based protocol for communication between its components, and version 11.221.03 and earlier versions contain a flaw in how authentication is processed for these connections. The software fails to properly validate the identity and authorization of connecting parties, allowing an unauthenticated attacker to craft TCP packets that are accepted as legitimate management console communications. Once the authentication check is bypassed, the attacker can send commands that the SKYSEA Client View service processes with its running privileges, effectively achieving remote code execution. Because endpoint management software typically runs with elevated system privileges to perform its management functions, the resulting code execution occurs at a high privilege level, giving the attacker comprehensive control over the compromised system.
Frequently Asked Questions
What is CVE-2016-7836?
CVE-2016-7836 is a critical remote code execution vulnerability in SKYSEA Client View version 11.221.03 and earlier. It allows an unauthenticated remote attacker to execute arbitrary code by exploiting a flaw in TCP authentication processing with the management console. The vulnerability has a CVSS score of 9.8 out of 10.
Why is a vulnerability from 2016 still relevant?
Despite being disclosed in 2016, CVE-2016-7836 remains actively exploited and has been added to CISA's KEV catalog with a 2025 remediation deadline. Its EPSS score of 35.34% (97.0th percentile) indicates ongoing attacker interest. Organizations that have not patched or decommissioned vulnerable SKYSEA Client View installations remain at critical risk.
What versions of SKYSEA Client View are affected?
All versions of SKYSEA Client View up to and including version 11.221.03 are affected. Organizations should upgrade to a version released after the vendor advisory of December 2016 to address this vulnerability.
Can this vulnerability be exploited remotely?
Yes. CVE-2016-7836 is remotely exploitable over the network without any authentication or user interaction. An attacker simply needs network access to the SKYSEA Client View management console TCP port to exploit the vulnerability, making it an ideal target for automated scanning and exploitation tools.
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