CVE-2011-4758 in Plesk Small Business Panel
Summary
by MITRE
Parallels Plesk Small Business Panel 10.2.0 receives cleartext password input over HTTP, which allows remote attackers to obtain sensitive information by sniffing the network, as demonstrated by forms in smb/auth and certain other files.
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Analysis
by VulDB Data Team • 01/29/2018
The vulnerability identified as CVE-2011-4758 represents a critical security flaw in Parallels Plesk Small Business Panel version 10.2.0 where cleartext passwords are transmitted over unencrypted HTTP connections. This weakness creates a significant attack surface that enables remote adversaries to intercept sensitive authentication credentials through network sniffing techniques. The vulnerability specifically affects authentication forms located within the smb/auth directory and other related files, making it particularly dangerous for environments where administrative access to the panel is required. The flaw directly violates fundamental security principles by failing to implement proper encryption mechanisms for sensitive data transmission, thereby exposing user credentials to man-in-the-middle attacks and passive network monitoring.
From a technical perspective, this vulnerability stems from the application's failure to utilize secure communication protocols for password transmission. The cleartext nature of the password input means that any network traffic containing authentication information can be easily captured by attackers using standard packet sniffing tools such as tcpdump, Wireshark, or similar network analysis utilities. The attack vector is particularly concerning because it operates at the network level rather than requiring exploitation of application-specific vulnerabilities, making it accessible to attackers with minimal technical expertise. The specific location of the vulnerable forms in the smb/auth directory suggests that this affects the authentication mechanism for shared file system access, potentially compromising not only user accounts but also system-level administrative privileges. This vulnerability aligns with CWE-312 (Cleartext Storage of Sensitive Information) and CWE-319 (Cleartext Transmission of Sensitive Information) classifications, which specifically address the improper handling of sensitive data in transmission and storage contexts.
The operational impact of this vulnerability extends beyond simple credential theft to potentially enable complete system compromise. An attacker who successfully intercepts cleartext passwords can gain unauthorized access to the Plesk panel and subsequently to all hosted websites and services managed through that interface. This creates a cascading security risk where a single compromised credential can provide access to multiple domains, email accounts, and potentially underlying server resources. The vulnerability is particularly dangerous in shared hosting environments or managed service providers where a single compromised administrative account can affect numerous customers. According to ATT&CK framework, this vulnerability maps to T1566 (Phishing for Information) and T1071.004 (Application Layer Protocol: DNS) as attackers can leverage the cleartext transmission to establish persistent access and potentially escalate privileges through additional attack vectors.
Organizations affected by this vulnerability should implement immediate mitigations including the enforcement of HTTPS encryption for all administrative interfaces, the implementation of network segmentation to prevent unauthorized packet capture, and the deployment of network monitoring tools to detect suspicious traffic patterns. The most effective long-term solution involves upgrading to a patched version of Parallels Plesk that implements proper SSL/TLS encryption for all authentication flows. Security administrators should also conduct comprehensive network audits to identify and remediate any additional cleartext transmission vulnerabilities within their infrastructure. Additionally, implementing mandatory encryption policies for all administrative communications and establishing secure remote access protocols such as SSH or VPN connections can significantly reduce the risk of credential interception. The vulnerability demonstrates the critical importance of implementing defense-in-depth strategies that protect against multiple attack vectors simultaneously, as network-level attacks can bypass traditional application-level security controls.