LibVNC before commit 73cb96fec028a576a5a24417b57723b55854ad7b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution

Several vulnerabilities have been identified in the VNC code of iTALC, a classroom management software. All vulnerabilities referenced below are issues that have originally been reported against Debian source package libvncserver. The italc source package in Debian ships a custom-patched version of libvncserver, thus libvncserver's security fixes required porting over.

CVE-2014-6051

Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer allowed remote VNC servers to cause a denial of service (crash) and possibly executed arbitrary code via an advertisement for a large screen size, which triggered a heap-based buffer overflow.

CVE-2014-6052

The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer did not check certain malloc return values, which allowed remote VNC servers to cause a denial of service (application crash) or possibly execute arbitrary code by specifying a large screen size in a (1) FramebufferUpdate, (2) ResizeFrameBuffer, or (3) PalmVNCReSizeFrameBuffer message.

CVE-2014-6053

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.

CVE-2014-6054

The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer allowed remote attackers to cause a denial of service (divide-by-zero error and server crash) via a zero value in the scaling factor in a (1) PalmVNCSetScaleFactor or (2) SetScale message.

CVE-2014-6055

Multiple stack-based buffer overflows in the File Transfer feature in rfbserver.c in LibVNCServer allowed remote authenticated users to cause a denial of service (crash) and possibly execute arbitrary code via a (1) long file or (2) directory name or the (3) FileTime attribute in a rfbFileTransferOffer message.

CVE-2016-9941

Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer allowed 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-2016-9942

Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer allowed 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 exceeded what is specified by the tile dimensions.

CVE-2018-6307

LibVNC contained heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

CVE-2018-7225

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.

CVE-2018-15126

LibVNC contained heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

CVE-2018-15127

LibVNC contained heap out-of-bound write vulnerability in server code of file transfer extension that can result remote code execution

CVE-2018-20749

LibVNC contained a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete.

CVE-2018-20750

LibVNC contained a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete.

CVE-2018-20019

LibVNC contained multiple heap out-of-bound write vulnerabilities in VNC client code that can result remote code execution

CVE-2018-20748

LibVNC contained multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.

CVE-2018-20020

LibVNC contained heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution

CVE-2018-20021

LibVNC contained a CWE-835: Infinite loop vulnerability in VNC client code. Vulnerability allows attacker to consume excessive amount of resources like CPU and RAM

CVE-2018-20022

LibVNC contained multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allowed attackers to read stack memory and could be abused for information disclosure. Combined with another vulnerability, it could be used to leak stack memory layout and in bypassing ASLR.

CVE-2018-20023

LibVNC contained CWE-665: Improper Initialization vulnerability in VNC Repeater client code that allowed attacker to read stack memory and could be abused for information disclosure. Combined with another vulnerability, it could be used to leak stack memory layout and in bypassing ASLR.

CVE-2018-20024

LibVNC contained NULL pointer dereference in VNC client code that could result DoS.

CVE-2019-15681

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 1:2.0.2+dfsg1-2+deb8u1.

We recommend that you upgrade your italc 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.

According to the versions of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - 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 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 commit     ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution.(CVE-2018-6307)

  - LibVNC before commit     73cb96fec028a576a5a24417b57723b55854ad7b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution(CVE-2018-15126)

  - 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 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)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - libvncserver: Heap out-of-bounds write in rfbserver.c     in rfbProcessFileTransferReadBuffer() allows for     potential code execution (CVE-2018-15127)

  - 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 commit     ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution.(CVE-2018-6307)

  - LibVNC before commit     73cb96fec028a576a5a24417b57723b55854ad7b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution(CVE-2018-15126)

  - 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 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)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - libvncserver: Heap out-of-bounds write in rfbserver.c     in rfbProcessFileTransferReadBuffer() allows for     potential code execution (CVE-2018-15127)

  - 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 commit     ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution.(CVE-2018-6307)

  - LibVNC before commit     73cb96fec028a576a5a24417b57723b55854ad7b contains heap     use-after-free vulnerability in server code of file     transfer extension that can result remote code     execution(CVE-2018-15126)

  - 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 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)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Pavel Cheremushkin discovered several vulnerabilities in libvncserver, a library to implement VNC server/client functionalities, which might result in the execution of arbitrary code, denial of service or information disclosure.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-3877-1 advisory.

    It was discovered that LibVNCServer incorrectly handled certain operations. A remote attacker able to     connect to applications using LibVNCServer could possibly use this issue to obtain sensitive information,     cause a denial of service, or execute arbitrary code.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

A vulnerability was found by Kaspersky Lab in libvncserver, a C library to implement VNC server/client functionalities. In addition, some of the vulnerabilities addressed in DLA 1617-1 were found to have incomplete fixes, and have been addressed in this update.

CVE-2018-15126

An attacker can cause denial of service or remote code execution via a heap use-after-free issue in the tightvnc-filetransfer extension.

CVE-2018-20748 CVE-2018-20749 CVE-2018-20750

Some of the out of bound heap write fixes for CVE-2018-20019 and CVE-2018-15127 were incomplete. These CVEs address those issues.

For Debian 8 'Jessie', these problems have been fixed in version 0.9.9+dfsg2-6.1+deb8u5.

We recommend that you upgrade your libvncserver 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.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

  - CVE-2018-15126: Fixed use-after-free in file transfer     extension (bsc#1120114)

  - CVE-2018-6307: Fixed use-after-free in file transfer     extension server code (bsc#1120115)

  - CVE-2018-20020: Fixed heap out-of-bound write inside     structure in VNC client code (bsc#1120116)

  - CVE-2018-15127: Fixed heap out-of-bounds write in     rfbserver.c (bsc#1120117)

  - CVE-2018-20019: Fixed multiple heap out-of-bound writes     in VNC client code (bsc#1120118)

  - CVE-2018-20023: Fixed information disclosure through     improper initialization in VNC Repeater client code     (bsc#1120119)

  - CVE-2018-20022: Fixed information disclosure through     improper initialization in VNC client code (bsc#1120120)

  - CVE-2018-20024: Fixed NULL pointer dereference in VNC     client code (bsc#1120121)

  - CVE-2018-20021: Fixed infinite loop in VNC client code     (bsc#1120122)

This update was imported from the SUSE:SLE-15:Update update project.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

CVE-2018-15126: Fixed use-after-free in file transfer extension (bsc#1120114)

CVE-2018-6307: Fixed use-after-free in file transfer extension server code (bsc#1120115)

CVE-2018-20020: Fixed heap out-of-bound write inside structure in VNC client code (bsc#1120116)

CVE-2018-15127: Fixed heap out-of-bounds write in rfbserver.c (bsc#1120117)

CVE-2018-20019: Fixed multiple heap out-of-bound writes in VNC client code (bsc#1120118)

CVE-2018-20022: Fixed information disclosure through improper initialization in VNC client code (bsc#1120120)

CVE-2018-20024: Fixed NULL pointer dereference in VNC client code (bsc#1120121)

CVE-2018-20021: Fixed infinite loop in VNC client code (bsc#1120122)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

CVE-2018-15126: Fixed use-after-free in file transfer extension (bsc#1120114)

CVE-2018-6307: Fixed use-after-free in file transfer extension server code (bsc#1120115)

CVE-2018-20020: Fixed heap out-of-bound write inside structure in VNC client code (bsc#1120116)

CVE-2018-15127: Fixed heap out-of-bounds write in rfbserver.c (bsc#1120117)

CVE-2018-20019: Fixed multiple heap out-of-bound writes in VNC client code (bsc#1120118)

CVE-2018-20023: Fixed information disclosure through improper initialization in VNC Repeater client code (bsc#1120119)

CVE-2018-20022: Fixed information disclosure through improper initialization in VNC client code (bsc#1120120)

CVE-2018-20024: Fixed NULL pointer dereference in VNC client code (bsc#1120121)

CVE-2018-20021: Fixed infinite loop in VNC client code (bsc#1120122)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

  - CVE-2018-15126: Fixed use-after-free in file transfer     extension (bsc#1120114)

  - CVE-2018-6307: Fixed use-after-free in file transfer     extension server code (bsc#1120115)

  - CVE-2018-20020: Fixed heap out-of-bound write inside     structure in VNC client code (bsc#1120116)

  - CVE-2018-15127: Fixed heap out-of-bounds write in     rfbserver.c (bsc#1120117)

  - CVE-2018-20019: Fixed multiple heap out-of-bound writes     in VNC client code (bsc#1120118)

  - CVE-2018-20023: Fixed information disclosure through     improper initialization in VNC Repeater client code     (bsc#1120119)

  - CVE-2018-20022: Fixed information disclosure through     improper initialization in VNC client code (bsc#1120120)

  - CVE-2018-20024: Fixed NULL pointer dereference in VNC     client code (bsc#1120121)

  - CVE-2018-20021: Fixed infinite loop in VNC client code     (bsc#1120122)

This update was imported from the SUSE:SLE-12:Update update project.

ID	Name	Product	Family	Severity
130408	Debian DLA-1979-1 : italc security update	Nessus	Debian Local Security Checks	critical
123109	EulerOS 2.0 SP3 : libvncserver (EulerOS-SA-2019-1096)	Nessus	Huawei Local Security Checks	critical
122378	EulerOS 2.0 SP2 : libvncserver (EulerOS-SA-2019-1051)	Nessus	Huawei Local Security Checks	critical
122206	EulerOS 2.0 SP5 : libvncserver (EulerOS-SA-2019-1033)	Nessus	Huawei Local Security Checks	critical
121561	Debian DSA-4383-1 : libvncserver - security update	Nessus	Debian Local Security Checks	critical
121541	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : LibVNCServer vulnerabilities (USN-3877-1)	Nessus	Ubuntu Local Security Checks	critical
121517	Debian DLA-1652-1 : libvncserver security update	Nessus	Debian Local Security Checks	critical
121282	openSUSE Security Update : LibVNCServer (openSUSE-2019-53)	Nessus	SuSE Local Security Checks	critical
121160	SUSE SLES11 Security Update : LibVNCServer (SUSE-SU-2019:13927-1)	Nessus	SuSE Local Security Checks	critical
121158	SUSE SLED15 / SLES15 Security Update : LibVNCServer (SUSE-SU-2019:0080-1)	Nessus	SuSE Local Security Checks	critical
121154	openSUSE Security Update : LibVNCServer (openSUSE-2019-45)	Nessus	SuSE Local Security Checks	critical
121094	SUSE SLES12 Security Update : LibVNCServer (SUSE-SU-2019:0060-1)	Nessus	SuSE Local Security Checks	critical

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