Multiple vulnerabilities in LibVNCServer

1) Use-after-free

EUVDB-ID: #VU16962

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-15126

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a heap use-after-free error in server code of file transfer extension. A remote attacker can trigger memory corruption and execute arbitrary code with elevated privileges.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-027-libvnc-heap-use-after-free/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Heap out-of-bounds write

EUVDB-ID: #VU17122

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-15127

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to heap out-of-bounds write in server code of file transfer extension. A remote attacker can trigger memory corruption and execute arbitrary code with elevated privileges.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-028-libvnc-heap-out-of-bound-write/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Heap out-of-bounds write

EUVDB-ID: #VU17123

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-20019

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to heap out-of-bounds write in VNC client code. A remote attacker can trigger memory corruption and execute arbitrary code with elevated privileges.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-029-libvnc-multiple-heap-out-of-bound-vulnerabilities/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

4) Heap out-of-bounds write

EUVDB-ID: #VU17124

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-20020

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to heap out-of-bounds write in inside structure in VNC client code. A remote attacker can trigger memory corruption and execute arbitrary code with elevated privileges.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-030-libvnc-heap-out-of-bound-write/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Infinite loop

EUVDB-ID: #VU17127

Risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-20021

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop in VNC client code. A remote attacker can consume excessive amount of resources like CPU and RAM and perform a denial of service (DoS) attack.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

6) Memory leak

EUVDB-ID: #VU17129

Risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-20022

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due memory leak in VNC Repeater client code. A remote attacker can read stack memory and bypass ASLR.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-032-libvnc-multiple-memory-leaks/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

7) Memory leak

EUVDB-ID: #VU17128

Risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-20023

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due memory leak in VNC Repeater client code. A remote attacker can read stack memory and bypass ASLR.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

8) NULL pointer dereference

EUVDB-ID: #VU17125

Risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-20024

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in VNC client code. A remote attacker can perform a denial of service (DoS) attack.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-034-libvnc-null-pointer-dereference/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

9) Heap use-after-free

EUVDB-ID: #VU17126

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-6307

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to heap use-after-free error in server code of file transfer extension. A remote attacker can trigger memory corruption and execute arbitrary code with elevated privileges.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

10) Heap out-of-bounds write

EUVDB-ID: #VU17751

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-20749

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error. A remote attacker can trigger out-of-bounds write in rfbserver.c and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://github.com/LibVNC/libvncserver/commit/a64c3b37af9a6c8f8009d7516874b8d266b42bae
https://github.com/LibVNC/libvncserver/commit/c2c4b81e6cb3b485fb1ec7ba9e7defeb889f6ba7
https://github.com/LibVNC/libvncserver/commit/c5ba3fee85a7ecbbca1df5ffd46d32b92757bc2a
https://github.com/LibVNC/libvncserver/commit/e34bcbb759ca5bef85809967a268fdf214c1ad2c
https://github.com/LibVNC/libvncserver/issues/273
https://www.openwall.com/lists/oss-security/2018/12/10/8

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

11) Heap out-of-bounds write

EUVDB-ID: #VU17750

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-20750

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error. A remote attacker can trigger out-of-bounds write in rfbserver.c and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://github.com/LibVNC/libvncserver/commit/a64c3b37af9a6c8f8009d7516874b8d266b42bae
https://github.com/LibVNC/libvncserver/commit/c2c4b81e6cb3b485fb1ec7ba9e7defeb889f6ba7
https://github.com/LibVNC/libvncserver/commit/c5ba3fee85a7ecbbca1df5ffd46d32b92757bc2a
https://github.com/LibVNC/libvncserver/commit/e34bcbb759ca5bef85809967a268fdf214c1ad2c
https://github.com/LibVNC/libvncserver/issues/273
https://www.openwall.com/lists/oss-security/2018/12/10/8

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

12) Heap out-of-bounds write

EUVDB-ID: #VU17749

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-20748

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error. A remote attacker can trigger out-of-bounds write in VNC client code and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update to version 0.9.12.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.11

CPE2.3

External links

https://github.com/LibVNC/libvncserver/commit/a64c3b37af9a6c8f8009d7516874b8d266b42bae
https://github.com/LibVNC/libvncserver/commit/c2c4b81e6cb3b485fb1ec7ba9e7defeb889f6ba7
https://github.com/LibVNC/libvncserver/commit/c5ba3fee85a7ecbbca1df5ffd46d32b92757bc2a
https://github.com/LibVNC/libvncserver/commit/e34bcbb759ca5bef85809967a268fdf214c1ad2c
https://github.com/LibVNC/libvncserver/issues/273
https://www.openwall.com/lists/oss-security/2018/12/10/8

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

Risk	High
Patch available	YES
Number of vulnerabilities	12
CVE-ID	CVE-2018-15126 CVE-2018-15127 CVE-2018-20019 CVE-2018-20020 CVE-2018-20021 CVE-2018-20022 CVE-2018-20023 CVE-2018-20024 CVE-2018-6307 CVE-2018-20749 CVE-2018-20750 CVE-2018-20748
CWE-ID	CWE-416 CWE-787 CWE-835 CWE-401 CWE-476
Exploitation vector	Network
Public exploit	N/A
Vulnerable software	LibVNCServer Server applications / Remote management servers, RDP, SSH
Vendor	LibVNC