SB2018121911 - Multiple vulnerabilities in LibVNCServer
Published: December 19, 2018 Updated: November 25, 2019
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 12 vulnerabilities.
1) Use-after-free (CVE-ID: CVE-2018-15126)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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
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.
2) Heap out-of-bounds write (CVE-ID: CVE-2018-15127)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
3) Heap out-of-bounds write (CVE-ID: CVE-2018-20019)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
4) Heap out-of-bounds write (CVE-ID: CVE-2018-20020)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
5) Infinite loop (CVE-ID: CVE-2018-20021)
CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
CVSSv4: 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
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.
6) Memory leak (CVE-ID: CVE-2018-20022)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 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
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.
7) Memory leak (CVE-ID: CVE-2018-20023)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 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
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.
8) NULL pointer dereference (CVE-ID: CVE-2018-20024)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: 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
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.
9) Heap use-after-free (CVE-ID: CVE-2018-6307)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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
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.
10) Heap out-of-bounds write (CVE-ID: CVE-2018-20749)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
11) Heap out-of-bounds write (CVE-ID: CVE-2018-20750)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
12) Heap out-of-bounds write (CVE-ID: CVE-2018-20748)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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
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.
Remediation
Install update from vendor's website.
References
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-027-libvnc-heap-use-after-free/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-028-libvnc-heap-out-of-bound-write/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-029-libvnc-multiple-heap-out-of-bound-vulnerabilities/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-030-libvnc-heap-out-of-bound-write/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-032-libvnc-multiple-memory-leaks/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-034-libvnc-null-pointer-dereference/
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/
- 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