CVE-2017-5257 in ePMP
Summary
by MITRE
In version 3.5 and prior of Cambium Networks ePMP firmware, an attacker who knows (or guesses) the SNMP read/write (RW) community string can insert XSS strings in certain SNMP OIDs which will execute in the context of the currently-logged on user.
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Analysis
by VulDB Data Team • 12/17/2019
The vulnerability identified as CVE-2017-5257 affects Cambium Networks ePMP firmware versions 3.5 and earlier, representing a critical cross-site scripting flaw that leverages SNMP management interfaces. This vulnerability resides within the firmware's handling of SNMP read-write community strings, creating a dangerous intersection between network management protocols and web-based security mechanisms. The flaw allows attackers to inject malicious JavaScript code through specific SNMP object identifiers, which then executes when processed by the web interface, fundamentally undermining the security boundaries between network management and user-facing applications.
The technical implementation of this vulnerability stems from improper input validation and sanitization within the SNMP OID processing logic. When an attacker possesses knowledge of or can guess the SNMP RW community string, they can manipulate specific OIDs to inject XSS payloads that persist in the device's configuration or monitoring interfaces. This flaw directly maps to CWE-79 Cross-site Scripting, where the vulnerability occurs due to insufficient validation of user-supplied data within the SNMP management interface. The execution context of these injected scripts operates within the privileges of the currently authenticated user, potentially enabling privilege escalation or session hijacking attacks.
The operational impact of CVE-2017-5257 extends beyond simple web-based attacks, as it provides attackers with a persistent means of executing malicious code on network infrastructure devices. This vulnerability affects network administrators who rely on SNMP for device monitoring and management, creating a dangerous scenario where legitimate management operations become vectors for exploitation. The attack surface includes any device running vulnerable firmware that exposes SNMP services, potentially compromising entire network segments if attackers can leverage this vulnerability to gain access to other networked systems. The vulnerability also aligns with ATT&CK technique T1078 Valid Accounts, as it requires knowledge of valid SNMP community strings but can lead to broader access within the network infrastructure.
Mitigation strategies for this vulnerability require immediate firmware updates to versions that address the XSS handling in SNMP interfaces, as well as network segmentation to limit SNMP access to trusted management stations. Organizations should implement strict SNMP community string policies with strong, unique credentials and consider disabling SNMPv1 and SNMPv2c where SNMPv3 is available. Network monitoring should include detection of suspicious SNMP OID modifications, and security teams should conduct regular vulnerability assessments targeting network infrastructure devices. The remediation process must also include comprehensive testing of updated firmware to ensure that the XSS vulnerability is properly addressed without introducing new issues in the management interfaces.