CVE-1999-1577: Buffer Overflow
Buffer overflow in HHOpen ActiveX control (hhopen.ocx) 1.0.0.1 for Internet Explorer 4.01 and 5 allows remote attackers to execute arbitrary commands via long arguments to the OpenHelp method.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Remove
Remove
hhopen.ocx (HHOpen ActiveX control)from your environment.Unregister and remove the vulnerable hhopen.ocx from affected systems running Internet Explorer 4.01 or 5. For example, unregister the control (e.g., regsvr32 /u hhopen.ocx), delete the hhopen.ocx file from the system, and reboot the host or restart Internet Explorer to ensure it is no longer loaded.
- Configuration
Tighten Internet Explorer security: disable or prompt for ActiveX controls in untrusted/Internet zones and disallow initialization/script of unsigned or unsafe ActiveX controls. Specifically, adjust Internet Options → Security for relevant zones to disable 'Initialize and script ActiveX controls not marked as safe' and other ActiveX-related settings, or otherwise block the hhopen ActiveX control from loading.
Internet Explorer ActiveX controls for affected security zones = Disable or restrict - Compensating control
Apply network and host-level mitigations to reduce exposure: restrict web browsing to trusted sites, use a proxy/URL filter or WAF to block pages that attempt to instantiate the HHOpen control, and restrict inbound access to systems running the affected Internet Explorer versions until the control is removed or mitigated.
Event History
Frequently Asked Questions
What is the severity of CVE-1999-1577?
CVE-1999-1577 has a high severity due to its potential for remote code execution through a buffer overflow.
How do I fix CVE-1999-1577?
To fix CVE-1999-1577, ensure you update Internet Explorer to the latest version that mitigates the vulnerability.
What software is affected by CVE-1999-1577?
CVE-1999-1577 affects Microsoft Internet Explorer versions 4.0.1 and 5.0 due to a vulnerability in the HHOpen ActiveX control.
What kind of attack is possible with CVE-1999-1577?
CVE-1999-1577 allows remote attackers to execute arbitrary commands on affected systems via specially crafted arguments.
Is CVE-1999-1577 still a concern today?
While CVE-1999-1577 dates back to 1999, systems still using vulnerable versions of Internet Explorer may still be at risk.