CVE-2008-1528 in ZyNOS
Summary
by MITRE
ZyXEL Prestige routers, including P-660, P-661, and P-662 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), allow remote authenticated users to obtain authentication data by making direct HTTP requests and then reading the HTML source, as demonstrated by a request for (1) RemMagSNMP.html, which discloses SNMP communities; or (2) WLAN.html, which discloses WEP keys.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/20/2018
The vulnerability identified as CVE-2008-1528 affects ZyXEL Prestige series routers including models P-660, P-661, and P-662, specifically those running firmware versions 3.40(AGD.2) through 3.40(AHQ.3). This represents a critical information disclosure flaw that undermines the security posture of these network devices by exposing sensitive authentication credentials to remote attackers who have already established authenticated access to the router's web interface. The vulnerability stems from improper access controls and insecure direct object references within the router's web administration interface, allowing authenticated users to bypass normal access restrictions and retrieve confidential information through direct HTTP requests to specific HTML pages. The flaw is particularly concerning as it demonstrates how a single authenticated session can be exploited to harvest multiple types of sensitive data including SNMP community strings and WEP wireless encryption keys that are fundamental to network security infrastructure.
The technical implementation of this vulnerability exploits the router's web server configuration where specific HTML pages contain embedded authentication data that should be protected from unauthorized access. When an authenticated user makes direct HTTP requests to pages such as RemMagSNMP.html or WLAN.html, the web server returns HTML source code containing sensitive information without proper authorization checks. This behavior violates fundamental security principles and represents a classic example of insecure direct object reference vulnerability categorized under CWE-284. The disclosure of SNMP communities allows attackers to potentially perform network reconnaissance, modify router configurations, or gain access to other network devices that rely on the same SNMP community strings for management purposes. Similarly, the exposure of WEP keys compromises the wireless network security, enabling attackers to decrypt wireless traffic and potentially gain network access through the wireless interface.
The operational impact of this vulnerability extends beyond simple credential theft to encompass broader network compromise potential. An attacker who gains initial authenticated access through legitimate means can escalate their privileges and access critical network infrastructure components without additional authentication requirements. The exposed SNMP communities could enable attackers to perform network mapping, monitor device status, and potentially manipulate router configurations through SNMP management operations. The WEP key disclosure particularly threatens wireless network security since WEP encryption is inherently weak and susceptible to various attacks, but the exposure of these keys significantly reduces the effective security of the wireless network. This vulnerability aligns with ATT&CK technique T1566 which involves credential harvesting through social engineering or exploitation of software vulnerabilities, and demonstrates how a single flaw can enable multiple attack vectors within a network infrastructure.
Mitigation strategies for this vulnerability should focus on immediate firmware updates provided by ZyXEL to address the insecure direct object reference implementation in the web interface. Network administrators should implement network segmentation to limit the impact of potential compromise and ensure that router administration interfaces are not directly accessible from untrusted networks. Access control measures should be strengthened through the use of strong authentication methods, network access control lists, and regular monitoring of administrative access logs. The vulnerability highlights the importance of proper input validation and access control implementation in web applications, particularly those managing network device configurations. Organizations should also consider implementing network monitoring solutions that can detect unusual patterns of access to administrative interfaces and alert on potential exploitation attempts. Regular security assessments of network infrastructure components should include verification of access controls and proper implementation of authentication mechanisms to prevent similar vulnerabilities from being introduced in future deployments.