Updated libvncserver packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6 and 7.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

LibVNCServer is a library that allows for easy creation of VNC server or client functionality.

An integer overflow flaw, leading to a heap-based buffer overflow, was found in the way screen sizes were handled by LibVNCServer. A malicious VNC server could use this flaw to cause a client to crash or, potentially, execute arbitrary code in the client. (CVE-2014-6051)

A NULL pointer dereference flaw was found in LibVNCServer's framebuffer setup. A malicious VNC server could use this flaw to cause a VNC client to crash. (CVE-2014-6052)

A NULL pointer dereference flaw was found in the way LibVNCServer handled certain ClientCutText message. A remote attacker could use this flaw to crash the VNC server by sending a specially crafted ClientCutText message from a VNC client. (CVE-2014-6053)

A divide-by-zero flaw was found in the way LibVNCServer handled the scaling factor when it was set to '0'. A remote attacker could use this flaw to crash the VNC server using a malicious VNC client.
(CVE-2014-6054)

Two stack-based buffer overflow flaws were found in the way LibVNCServer handled file transfers. A remote attacker could use this flaw to crash the VNC server using a malicious VNC client.
(CVE-2014-6055)

Red Hat would like to thank oCERT for reporting these issues. oCERT acknowledges Nicolas Ruff as the original reporter.

All libvncserver users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.
All running applications linked against libvncserver must be restarted for this update to take effect.

Updated kdenetwork packages that fix three security issues are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

The kdenetwork packages contain networking applications for the K Desktop Environment (KDE). Krfb Desktop Sharing, which is a part of the kdenetwork package, is a server application that allows session sharing between users. Krfb uses the LibVNCServer library.

A NULL pointer dereference flaw was found in the way LibVNCServer handled certain ClientCutText message. A remote attacker could use this flaw to crash the VNC server by sending a specially crafted ClientCutText message from a VNC client. (CVE-2014-6053)

A divide-by-zero flaw was found in the way LibVNCServer handled the scaling factor when it was set to '0'. A remote attacker could use this flaw to crash the VNC server using a malicious VNC client.
(CVE-2014-6054)

Two stack-based buffer overflow flaws were found in the way LibVNCServer handled file transfers. A remote attacker could use this flaw to crash the VNC server using a malicious VNC client.
(CVE-2014-6055)

Red Hat would like to thank oCERT for reporting these issues. oCERT acknowledges Nicolas Ruff as the original reporter.

Note: Prior to this update, the kdenetwork packages used an embedded copy of the LibVNCServer library. With this update, the kdenetwork packages have been modified to use the system LibVNCServer packages.
Therefore, the update provided by RHSA-2014:1826 must be installed to fully address the issues in krfb described above.

All kdenetwork users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. All running instances of the krfb server must be restarted for this update to take effect.

Updated libvncserver packages fix security vulnerabilities :

A malicious VNC server can trigger incorrect memory management handling by advertising a large screen size parameter to the VNC client. This would result in multiple memory corruptions and could allow remote code execution on the VNC client (CVE-2014-6051, CVE-2014-6052).

A malicious VNC client can trigger multiple DoS conditions on the VNC server by advertising a large screen size, ClientCutText message length and/or a zero scaling factor parameter (CVE-2014-6053, CVE-2014-6054).

A malicious VNC client can trigger multiple stack-based buffer overflows by passing a long file and directory names and/or attributes (FileTime) when using the file transfer message feature (CVE-2014-6055).

Additionally libvncserver has been built against the new system minilzo library which is also being provided with this advisory.

The LibVNCServer package was updated to fix the following security issues :

  - bsc#897031: fix several security issues :

  - CVE-2014-6051: Integer overflow in MallocFrameBuffer()     on client side.

  - CVE-2014-6052: Lack of malloc() return value checking on     client side.

  - CVE-2014-6053: Server crash on a very large     ClientCutText message.

  - CVE-2014-6054: Server crash when scaling factor is set     to zero.

  - CVE-2014-6055: Multiple stack overflows in File Transfer     feature.

  - bsc#854151: Restrict the SSL cipher suite.

The remote Ubuntu 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4587-1 advisory.

    Nicolas Ruff discovered that iTALC had buffer overflows, divide-by-zero errors and didn't check malloc     return values. A remote attacker could use these issues to cause a denial of service or possibly execute     arbitrary code. (CVE-2014-6051, CVE-2014-6052, CVE-2014-6053, CVE-2014-6054, CVE-2014-6055)

    Josef Gajdusek discovered that iTALC had heap-based buffer overflow vulnerabilities. A remote attacker     could used these issues to cause a denial of service or possibly execute arbitrary code. (CVE-2016-9941,     CVE-2016-9942)

    It was discovered that iTALC had an out-of-bounds write, multiple heap out-of-bounds writes, an infinite     loop, improper initializations, and null pointer vulnerabilities. A remote attacker could used these     issues to cause a denial of service or possibly execute arbitrary code. (CVE-2018-15127, CVE-2018-20019,     CVE-2018-20020, CVE-2018-20021, CVE-2018-20022, CVE-2018-20023, CVE-2018-20024, CVE-2018-20748,     CVE-2018-20749, CVE-2018-20750, CVE-2018-7225, CVE-2019-15681)

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.

ID	名前	製品	ファミリー	公開日	更新日	深刻度
79202	RHEL 6 / 7 : libvncserver (RHSA-2014:1826)	Nessus	Red Hat Local Security Checks	2014/11/12	2021/1/14	high
79203	RHEL 7 : kdenetwork (RHSA-2014:1827)	Nessus	Red Hat Local Security Checks	2014/11/12	2021/1/14	medium
79219	CentOS 7 : kdenetwork (CESA-2014:1827)	Nessus	CentOS Local Security Checks	2014/11/13	2021/1/4	medium
79589	Mandriva Linux Security Advisory : libvncserver (MDVSA-2014:229)	Nessus	Mandriva Local Security Checks	2014/11/27	2021/1/6	high
87389	openSUSE Security Update : LibVNCServer (openSUSE-2015-851)	Nessus	SuSE Local Security Checks	2015/12/16	2021/1/19	high
141545	Ubuntu 16.04 LTS : iTALC vulnerabilities (USN-4587-1)	Nessus	Ubuntu Local Security Checks	2020/10/20	2024/8/27	critical

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