CVE-2017-6776 in Elastic Services Controller
Summary
by MITRE
A vulnerability in the web framework of Cisco Elastic Services Controller (ESC) could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web interface. The vulnerability is due to insufficient validation of user-supplied input by the affected software. An attacker could exploit this vulnerability by convincing a user to access a malicious link or by intercepting a user request and injecting malicious code into the request. An exploit could allow the attacker to execute arbitrary script code in the context of the affected site or allow the attacker to access sensitive browser-based information. Cisco Bug IDs: CSCvd76324. Known Affected Releases: 2.2(9.76) and 2.3(1).
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Analysis
by VulDB Data Team • 01/09/2021
The vulnerability identified as CVE-2017-6776 resides within the web framework of Cisco Elastic Services Controller version 2.2(9.76) and 2.3(1), representing a critical cross-site scripting flaw that undermines the security posture of the affected system. This vulnerability stems from inadequate input validation mechanisms within the web interface, creating an exploitable entry point for malicious actors. The flaw specifically affects the ESC's handling of user-supplied data, where insufficient sanitization allows attacker-controlled content to persist and execute within the victim's browser context. The vulnerability manifests as a classic XSS attack vector that can be leveraged by unauthenticated remote threat actors without requiring any privileged access or credentials to initiate the exploitation process.
The technical implementation of this vulnerability aligns with CWE-79, which categorizes cross-site scripting as a weakness where untrusted input is improperly validated or escaped before being rendered in web applications. The attack surface is particularly concerning as it operates through standard web browser interactions where users are tricked into clicking malicious links or when attackers intercept legitimate user requests and inject harmful script payloads. The exploitation mechanism exploits the fundamental trust relationship between the web application and its users, allowing malicious code to execute with the privileges of the victim's browser session. This creates a persistent threat vector where attackers can access sensitive browser-based information, manipulate web page content, or potentially hijack user sessions through session cookie theft.
The operational impact of CVE-2017-6776 extends beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal user credentials, or redirect victims to malicious domains. The vulnerability's remote and unauthenticated nature means that attackers can exploit it from anywhere on the internet without requiring physical access or network proximity to the target system. This characteristic significantly amplifies the attack surface and makes the vulnerability particularly dangerous for organizations relying on the ESC for their network services. The affected releases 2.2(9.76) and 2.3(1) represent specific software versions where the input validation mechanisms were insufficiently implemented, creating a window of opportunity for threat actors to compromise user sessions and potentially gain access to sensitive network information.
Mitigation strategies for this vulnerability should prioritize immediate software updates to patched versions that address the input validation deficiencies. Organizations must implement comprehensive web application firewall rules to detect and block suspicious input patterns that could indicate XSS attempts. Network segmentation and monitoring solutions should be deployed to detect anomalous traffic patterns that may suggest exploitation attempts. The vulnerability's classification under the ATT&CK framework aligns with techniques such as T1059.007 for script injection and T1566 for social engineering attacks that leverage user trust. Security teams should also implement proper input sanitization practices and conduct regular security assessments to identify similar validation weaknesses in other web applications. The remediation process requires careful coordination to ensure that patches do not disrupt existing network services while maintaining the integrity of the ESC's operational functionality.