LibVNCServer rfbProcessClientNormalMessage() Function Information Disclosure Vulnerability [CVE-2018-7225]
CVE Number – CVE-2018-7225
A vulnerability in the rfbProcessClientNormalMessage() function of LibVNCServer could allow an attacker to gain access to sensitive information on a targeted system.
The vulnerability exists because the affected software does not properly sanitize msg.cct length values when the rfbProcessClientNormalMessage() function, as defined in the rfbserver.c source code file of the affected software, is used. An attacker could exploit this vulnerability to access uninitialized memory and potentially sensitive information on a targeted system.
The vendor has confirmed the vulnerability and released software patches.
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To exploit this vulnerability, the attacker must send crafted VNC packets to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
Exploitation of this vulnerability could also trigger an integer overflow condition, which could have other unspecified impacts on an affected system.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
Administrators are advised to monitor affected systems.
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The vendor has released a bug report at the following link: Security: libvncserver/rfbserver.c: rfbProcessClientNormalMessage() case rfbClientCutText doesn’t sanitize msg.cct.length #218
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The vendor has released software patches at the following links: Limit client cut text length to 1 MB and Validate client cut text length
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Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.