CVE-2007-0617 in Total Access
Summary
by MITRE
The SpamBlocker.dll ActiveX control in Earthlink TotalAccess is marked "safe for scripting," which allows remote attackers to add arbitrary e-mail addresses and domains to the spam blocker whitelist via the (1) AddSenderToWhitelist and (2) AddDomainToWhitelist functions.
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Analysis
by VulDB Data Team • 10/07/2017
The vulnerability described in CVE-2007-0617 represents a critical security flaw in the Earthlink TotalAccess software's SpamBlocker.dll ActiveX control. This issue stems from improper security design where the control is incorrectly marked as "safe for scripting" despite containing functionality that should be restricted. The vulnerability specifically affects the whitelist management capabilities of the spam filtering system, creating an attack vector that allows remote exploitation without user interaction. The flaw exists in the ActiveX control's implementation where legitimate administrative functions are exposed to unauthenticated remote attackers through the browser environment.
The technical exploitation of this vulnerability occurs through the two exposed functions AddSenderToWhitelist and AddDomainToWhitelist within the SpamBlocker.dll control. When a user visits a malicious website containing crafted ActiveX code, these functions can be invoked remotely to add arbitrary email addresses and domains to the spam blocker's whitelist. This creates a persistent backdoor that allows attackers to bypass spam filtering mechanisms and potentially deliver malicious emails directly to the user's inbox. The vulnerability is particularly dangerous because it leverages the browser's ActiveX security model, which is designed to execute trusted components but fails to properly validate the legitimacy of requests made to the control.
The operational impact of this vulnerability extends beyond simple spam bypassing, as it fundamentally undermines the security posture of the affected system. Attackers can use this capability to whitelist known malicious senders, making it possible to deliver phishing emails, malware distribution payloads, or other malicious content without detection. The persistent nature of the whitelist modifications means that once an attacker successfully exploits this vulnerability, their malicious domains or addresses remain whitelisted until manually removed by a system administrator. This vulnerability aligns with CWE-284 (Improper Access Control) and represents a classic case of privilege escalation through insecure ActiveX control implementation. The attack vector is particularly concerning because it requires no user interaction beyond visiting a malicious website, making it a prime target for drive-by download attacks.
Mitigation strategies for this vulnerability must address both the immediate exposure and the underlying architectural issues. System administrators should immediately disable or remove the vulnerable ActiveX control from affected systems and update the Earthlink TotalAccess software to versions that properly secure the SpamBlocker.dll component. Browser security configurations should be adjusted to restrict ActiveX control execution, particularly for controls marked as "safe for scripting" that contain administrative functions. Network-level protections such as content filtering and email security appliances should be implemented to provide additional layers of defense against the types of malicious emails that could be whitelisted through this vulnerability. This remediation approach aligns with ATT&CK technique T1190 (Exploit Public-Facing Application) and addresses the fundamental security principle that administrative functions should never be exposed to unauthenticated remote access. Organizations should also implement regular security assessments of ActiveX controls and browser extensions to identify similar vulnerabilities in other software components.