CVE-2011-2545 in Spa 502g 1-line Ip Phone
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the SIP implementation on the Cisco SPA8000 and SPA8800 before 6.1.11, SPA2102 and SPA3102 before 5.2.13, and SPA 500 series IP phones before 7.4.9 allows remote attackers to inject arbitrary web script or HTML via the FROM field of an INVITE message, aka Bug IDs CSCtr27277, CSCtr27256, CSCtr27274, and CSCtr14715.
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Analysis
by VulDB Data Team • 02/17/2019
The CVE-2011-2545 vulnerability represents a critical cross-site scripting flaw within Cisco's SIP implementation across multiple IP phone models including SPA8000, SPA8800, SPA2102, SPA3102, and various SPA500 series devices. This vulnerability specifically affects firmware versions prior to 6.1.11 for SPA8000/8800 series, 5.2.13 for SPA2102/3102 series, and 7.4.9 for SPA500 series devices. The flaw resides in the improper validation and sanitization of input parameters within the SIP protocol handling mechanism, particularly concerning the FROM field of INVITE messages.
The technical exploitation of this vulnerability occurs through the manipulation of the SIP INVITE message's FROM field, which is processed by the affected Cisco IP phones. When a malicious attacker crafts a specially formatted INVITE message containing malicious script code within the FROM field, the vulnerable devices fail to properly sanitize this input before displaying it to users. This allows attackers to inject arbitrary web scripts or HTML content that executes within the context of the user's browser session when the phone interface displays the malicious SIP message. The vulnerability stems from insufficient input validation and output encoding practices in the SIP message processing pipeline, creating an attack surface that directly enables code execution in the victim's browser environment.
The operational impact of this vulnerability is significant as it allows remote attackers to conduct various malicious activities including session hijacking, credential theft, and unauthorized access to phone functionalities. Attackers can exploit this vulnerability to redirect users to malicious websites, steal session cookies, or inject phishing content that appears legitimate within the phone's user interface. The vulnerability affects not only individual devices but also creates potential risks for entire network infrastructures, as compromised phones can serve as entry points for broader network infiltration. This weakness directly violates the principle of input validation and can be categorized under CWE-79 as "Cross-site Scripting" and aligns with ATT&CK technique T1566.001 for "Phishing" and T1071.004 for "Application Layer Protocol: SIP" in network protocol exploitation.
Mitigation strategies for CVE-2011-2545 should prioritize immediate firmware updates to the latest available versions for all affected Cisco IP phone models, as these updates contain proper input sanitization and validation mechanisms. Network administrators should implement SIP message filtering and validation at network boundaries to detect and block malicious INVITE messages before they reach endpoint devices. Additional protective measures include configuring firewalls to restrict SIP traffic to trusted sources, implementing network segmentation to isolate voice infrastructure, and conducting regular security assessments of VoIP environments. Organizations should also establish monitoring procedures to detect anomalous SIP traffic patterns that might indicate exploitation attempts, while ensuring that all network devices maintain current security patches and that user access controls are properly configured to minimize potential attack surface.