Zhone ADSL2+ 4P Authentiation Bypass / Information Disclosure
Posted on 04 September 2015
Document Title: =============== Zhone ADSL2+ 4P Bridge & Router (Broadcom) - Multiple Vulnerabilities References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=1591 Download: http://www.zhone.com/support/downloads/cpe/6218-I2/6218-I2_R030220_AnnexA.zip Release Date: ============= 2015-09-03 Vulnerability Laboratory ID (VL-ID): ==================================== 1591 Common Vulnerability Scoring System: ==================================== 8.8 Product & Service Introduction: =============================== At Zhone, Bandwidth Changes Everything™ is more than just a tag line. It is our focus, our fundamental belief and philosophy in developing carrier and enterprise-grade fiber access solutions for our customers ensuring bandwidth is never a constraint in the future! (Copy of the Vendor Homepage: http://www.zhone.com/support/ ) Abstract Advisory Information: ============================== An independent vulnerability laboratory researcher discovered multiple remote vulnerabilities in the official Zhone ADSL2+ 4 Port Wireless Bridge & Router (Broadcom). Vulnerability Disclosure Timeline: ================================== 2015-09-03: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== Zhone Product: Zhone ADSL2+ 4 Port Bridge (Broadcom) & Zhone ADSL2+ 4 Port Router (Broadcom) 6218-I2-xxx - FW: 03.02.20 Exploitation Technique: ======================= Remote Severity Level: =============== High Technical Details & Description: ================================ An authentication bypass vulnerability has been discovered in the official in the official Zhone ADSL2+ 4 Port Wireless Bridge & Router (Broadcom). The vulnerability allows remote attackers to bypass the authentication procedure to compromise the hardware device or service interface. The first vulnerability is located in the session validation when processing to request via GET (outside the network) the `pvccfg.cgi`,`dnscfg.cgi` and `password.cgi` files. Thus can results in a reconfiguration by the attacker to compromise the hardware device. The second vulnerability is located in the backupsettings.conf file access rights. Remote attackers can easily request via curl the backupsettings of the hardware device. Thus can result in an easy take-over of the hardware device via an information disclosure by accessing the backupsettings.conf. The security risk of both vulnerabilities are estimated as high with a cvss (common vulnerability scoring system) count of 8.8. Exploitation of the access privilege issue requires no privilege application user account or user interaction. Successful exploitation of the bug results in hardware device compromise. Request Method(s): [+] GET Vulnerable Model(s): [+] Zhone ADSL2+ 4 Port Bridge (Broadcom) [+] Zhone ADSL2+ 4 Port Router (Broadcom) Affected Firmware: [+] 03.02.20 Product Name: [+] 6218-I2-xxx Proof of Concept (PoC): ======================= The vulnerabilities can be exploited by remote attackers without privilege device user account or user interaction. For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue. PoC: #1 http://[LOCALHOST]:?/pvccfg.cgi http://[LOCALHOST]:?/dnscfg.cgi http://[LOCALHOST]:?/password.cgi (In addition to text storage of sensitive information!) Note: The links above can be accessed without any authentication in the interface! PoC: #2 curl "http://<IP>/backupsettings.conf" -H "Authorization: Basic dXNlcjp1c2Vy" ("dXNlcjp1c2Vy" = "user:user" in base64) Note: Obtaining backup DSL router configurations by an users account authentication! Security Risk: ============== The security risk of the both vulnerabilities in the bridge and wireless router interface is estimated as high. (CVSS 8.8) Credits & Authors: ================== Mahmoud Khaled - [mahmoud_khld@yahoo.com] Disclaimer & Information: ========================= The information provided in this advisory is provided as it is without any warranty. Vulnerability Lab disclaims all warranties, either expressed or implied, including the warranties of merchantability and capability for a particular purpose. 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