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RHEL 6 : libvncserver (Unpatched Vulnerability)

critical Nessus Plugin ID 196364

Synopsis

The remote Red Hat 6 host is affected by multiple vulnerabilities that will not be patched.

Description

The remote Redhat Enterprise Linux 6 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

 - libvncserver: Improper input sanitization in rfbProcessClientNormalMessage in rfbserver.c (CVE-2018-7225)

 - Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted FramebufferUpdate message containing a subrectangle outside of the client drawing area. (CVE-2016-9941)

 - Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted FramebufferUpdate message with the Ultra type tile, such that the LZO payload decompressed length exceeds what is specified by the tile dimensions. (CVE-2016-9942)

 - LibVNC before commit 502821828ed00b4a2c4bef90683d0fd88ce495de contains heap out-of-bound write vulnerability in server code of file transfer extension that can result remote code execution (CVE-2018-15127)

 - LibVNC before commit a83439b9fbe0f03c48eb94ed05729cb016f8b72f contains multiple heap out-of-bound write vulnerabilities in VNC client code that can result remote code execution (CVE-2018-20019)

 - LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution (CVE-2018-20020)

 - LibVNC before 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838 contains multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allows attacker to read stack memory and can be abuse for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and in bypassing ASLR (CVE-2018-20022)

 - LibVNC before commit 4a21bbd097ef7c44bb000c3bd0907f96a10e4ce7 contains null pointer dereference in VNC client code that can result DoS. (CVE-2018-20024)

 - LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete. (CVE-2018-20748)

 - LibVNC before 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete. (CVE-2018-20749)

 - LibVNC through 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete. (CVE-2018-20750)

 - LibVNC commit before d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a contains a memory leak (CWE-655) in VNC server code, which allow an attacker to read stack memory and can be abused for information disclosure.
 Combined with another vulnerability, it can be used to leak stack memory and bypass ASLR. This attack appear to be exploitable via network connectivity. These vulnerabilities have been fixed in commit d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a. (CVE-2019-15681)

 - libvncserver: HandleCursorShape() integer overflow resulting in heap-based buffer overflow (CVE-2019-15690)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer dereference. (CVE-2020-14397)

 - An issue was discovered in LibVNCServer before 0.9.13. An improperly closed TCP connection causes an infinite loop in libvncclient/sockets.c. (CVE-2020-14398)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/scale.c has a pixel_value integer overflow. (CVE-2020-14401)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/corre.c allows out-of-bounds access via encodings. (CVE-2020-14402)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/hextile.c allows out-of-bounds access via encodings. (CVE-2020-14403)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rre.c allows out-of-bounds access via encodings. (CVE-2020-14404)

 - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat size. (CVE-2020-14405)

 - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw to send a specially crafted message that, when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service. (CVE-2020-25708)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

Solution

The vendor has acknowledged the vulnerabilities but no solution has been provided. Refer to the vendor for remediation guidance.

Plugin Details

Severity: Critical

ID: 196364

File Name: redhat_unpatched-libvncserver-rhel6.nasl

Version: 1.0

Type: local

Agent: unix

Published: 5/11/2024

Updated: 5/11/2024

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2018-7225

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:6, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:redhat:enterprise_linux:libvncserver, p-cpe:/a:redhat:enterprise_linux:vino

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 12/31/2016

Reference Information

CVE: CVE-2016-9941, CVE-2016-9942, CVE-2018-15127, CVE-2018-20019, CVE-2018-20020, CVE-2018-20022, CVE-2018-20024, CVE-2018-20748, CVE-2018-20749, CVE-2018-20750, CVE-2018-7225, CVE-2019-15681, CVE-2019-15690, CVE-2020-14397, CVE-2020-14398, CVE-2020-14401, CVE-2020-14402, CVE-2020-14403, CVE-2020-14404, CVE-2020-14405, CVE-2020-25708