SynopsisThe remote Debian host is missing a security update.
DescriptionSeveral vulnerabilities have been identified in the VNC code of vino, a desktop sharing utility for the GNOME desktop environment.
The vulnerabilities referenced below are issues that have originally been reported against Debian source package libvncserver. The vino source package in Debian ships a custom-patched and stripped down variant of libvncserver, thus some of libvncserver's security fixes required porting over.
The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer did not properly handle attempts to send a large amount of ClientCutText data, which allowed remote attackers to cause a denial of service (memory consumption or daemon crash) via a crafted message that was processed by using a single unchecked malloc.
An issue was discovered in LibVNCServer.
rfbProcessClientNormalMessage() in rfbserver.c did not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact (e.g., an integer overflow) via specially crafted VNC packets.
LibVNC contained a memory leak (CWE-655) in VNC server code, which allowed an attacker to read stack memory and could be abused for information disclosure. Combined with another vulnerability, it could be used to leak stack memory and bypass ASLR. This attack appeared to be exploitable via network connectivity.
For Debian 8 'Jessie', these problems have been fixed in version 3.14.0-2+deb8u1.
We recommend that you upgrade your vino packages.
NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpgrade the affected vino package.