ID

VAR-201807-1638

CVE

CVE-2018-3667

TITLE

Installation tool IPDT Vulnerabilities related to authorization, permissions, and access control

DESCRIPTION

Installation tool IPDT (Intel Processor Diagnostic Tool) 4.1.0.24 sets permissions of installed files incorrectly, allowing for execution of arbitrary code and potential privilege escalation. Intel Processor Diagnostic Tool (IPDT) is a processor function diagnostic tool of Intel Corporation. Intel published advisory SA-00140 <https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00140.html> on 2018-06-27 and updated installers on 2018-05-18. The vulnerabilities can be exploited in standard installations of Windows where the user^WUAC-"protected administrator" account created during Windows setup is used, without elevation. This precondition holds for the majority of Windows installations: according to Microsoft's own security intelligence reports <https://www.microsoft.com/security/sir>, about 1/2 to 3/4 of the about 600 million Windows installations which send telemetry data have only ONE active user account. #1 Denial of service through insecure file permissions ====================================================== The downloadable executable installer (really: executable self-extractor built with WinZIP) IPDT_Installer_4.1.0.24.exe creates a subdirectory with random name in %TEMP%, copies itself into this subdirectory and then executes its copy. The subdirectory inherits the NTFS ACLs from its parent %TEMP%, and so does the copy of the executable self-extractor. For this well-known and well-documented vulnerability see <https://cwe.mitre.org/data/definitions/377.html> and <https://cwe.mitre.org/data/definitions/379.html> plus <https://capec.mitre.org/data/definitions/29.html> Proof of concept/demonstration: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. download IPDT_Installer_4.1.0.24.exe (quite some clueless copycats still offer it, violating Intel's copyright; <http://d.computerbild.de/downloads/7835763/IPDT_Installer_4.1.0.24.exe>) and save it in your "Downloads" directory"; 2. add the NTFS access control list entry (D;OIIO;WP;;;WD) meaning "deny execution of files in this directory for everyone, inheritable to files in all subdirectories" to the (user's) %TEMP% directory. 3. execute IPDT_Installer_4.1.024.exe: notice the complete failure of the executable installer^Wself-extractor, WITHOUT error message! #2 Escalation of privilege through insecure file permissions ============================================================ Although the (copy of the) executable self-extractor runs with administrative privileges (its embedded "application manifest" specifies 'requireAdministrator'), it extracts its payload, the REAL installers setup.exe and setup64.exe, plus the batch script setup.bat, UNPROTECTED into the user's %TEMP% directory, CD's into %TEMP% and finally executes the extracted batch script %TEMP%\setup.bat: --- setup.bat --- echo off ver | findstr 6.1.7600 if %errorlevel%==0 goto WinUnsup ver | findstr 6.0.6001 if %errorlevel%==0 goto WinUnsup if "%programfiles(x86)%XXX"=="XXX" goto 32BIT :64BIT setup64.exe goto END :32BIT setup.exe goto END :WinUnsup echo Intel Processor Diagnostic Tool cannot be installed on this Operating System echo Please go to Online support page to view list of supported Oerating Systems pause :END exit 0 --- EOF --- The extracted files inherit the NTFS ACLs from their parent %TEMP%, allowing "full access" for the unprivileged (owning) user, who can replace/overwrite the files between their creation and execution. Proof of concept/demonstration: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. create the following batch script in an arbitrary directory: --- IPDT.CMD --- :LOOP1 @If Not Exist "%TEMP%\setup.exe" Goto :LOOP1 Echo >"%TEMP%\setup.bat" WhoAMI.exe /all Echo >>"%TEMP%\setup.bat" Pause :LOOP2 @If Not Exist "%TEMP%\setup64.exe" Goto :LOOP2 Copy /Y %COMSPEC% "%TEMP%\setup.exe" :LOOP3 @Copy %COMSPEC% "%TEMP%\setup64.exe" @If ERRORLEVEL 1 Goto :LOOP3 --- EOF --- NOTE: the batch script needs to win a race (which it almost always will, due to the size of the files extracted). 2. execute the batch script per double-click; 3. execute IPDT_Installer_4.1.024.exe per double-click: notice the command processor started instead one of the executable installers, running with administrative privileges. #3 Escalation of privilege through unsafe search path ===================================================== In Windows Vista and newer versions, the current working directory can be removed from the executable search path: <https://msdn.microsoft.com/en-us/library/ms684269.aspx> The batch script setup.bat calls setup.exe and setup64.exe without a path, so the command processor doesn't find the extracted setup.exe and setup64.exe in its CWD and searches them via %PATH%. %PATH% is under full control of the unprivileged user, who can create rogue setup.exe and setup64.exe in an arbitrary directory he adds to the %PATH%, resulting again in arbitrary code execution with escalation of privilege. For this well-known and well-documented vulnerability see <https://cwe.mitre.org/data/definitions/426.html> and <https://cwe.mitre.org/data/definitions/427.html> plus <https://capec.mitre.org/data/definitions/471.html>. Proof of concept/demonstration: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. start an unprivileged command prompt in an arbitrary directory where the unprivileged user can create files, for example the user's "Downloads" directory; 2. add this (current working) directory to the user's PATH: PATH %CD%;%PATH% REG.exe Add HKCU\Environment /V PATH /T REG_SZ /D "%CD%" /F 3. copy the command processor %COMSPEC% (or any rogue executable of your choice) as setup.exe and setup64.exe into the current (working) directory: COPY %COMSPEC% "%CD%\setup.exe" COPY %COMSPEC% "%CD%\setup64.exe" 4. set the environment variable NoDefaultCurrentDirectoryInExePath to an arbitrary value: SET NoDefaultCurrentDirectoryInExePath=* REG.exe Add HKCU\Environment /V NoDefaultCurrentDirectoryInExePath /T REG_SZ /D "*" /F 5. execute IPDT_Installer_4.1.024.exe per double-click: notice the command processor started instead of the extracted executable installers, running with administrative privileges. #4 Escalation of privilege through DLL search order hijacking ============================================================= The extracted executable installers setup.exe and setup64.exe, built with the crapware known as InstallShield, load multiple Windows system DLLs from their "application directory" %TEMP% instead from Windows' "system directory" %SystemRoot%\System32\ To quote Raymond Chen <https://blogs.msdn.microsoft.com/oldnewthing/20121031-00/?p=6203> | a rogue DLL in the TEMP directory is a trap waiting to be sprung. An unprivileged attacker running in the same user account can copy rogue DLLs into %TEMP%; these are loaded and their DllMain() routine executed with administrative privileges, once more resulting in arbitrary code execution with escalation of privilege. For this well-known and well-documented vulnerability see <https://cwe.mitre.org/data/definitions/426.html> and <https://cwe.mitre.org/data/definitions/427.html> plus <https://capec.mitre.org/data/definitions/471.html>. Proof of concept/demonstration: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. follow the instructions from <https://skanthak.homepage.t-online.de/minesweeper.html> and build a minefield of forwarder DLLs in your %TEMP% directory; NOTE: if you can't or don't want to build the minefield, download <https://skanthak.homepage.t-online.de/download/SENTINEL.DLL> and save it as UXTheme.dll, DWMAPI.dll, NTMARTA.dll and MSI.dll in your %TEMP% directory. 2. execute IPDT_Installer_4.1.0.24.exe: notice the message boxes displayed from the DLLs built in step 1! NOTE: on a fully patched Windows 7 SP1, setup64.exe loads at least the following 32-bit DLLs from %TEMP%: UXTheme.dll, Version.dll, NTMARTA.dll and MSI.dll Due to its filename, setup.exe additionally loads WinMM.dll, SAMCli.dll, MSACM32.dll, SFC.dll, SFC_OS.dll, DWMAPI.dll and MPR.dll. Fix: ==== 1. DUMP all those forever vulnerable executable installers and self-extractors; provide an .MSI package or an .INF script plus a .CAB archive instead! 2. NEVER use an unqualified filename to execute/load an application or a DLL, ALWAYS specify their fully qualified pathname! Mitigations: ============ 1. DON'T execute executable self-extractors. 2. NEVER execute executable self-extractors with administrative privileges. 3. extract the payload of the self-extractor with a SAFE and SECURE unzip.exe into a properly protected directory. 4. exercise STRICT privilege separation: use separate unprivileged user accounts and privileged administrator account, DISABLE the "security theatre" UAC in the unprivileged user accounts. stay tuned Stefan Kanthak PS: the "portable executable" IPDT_Installer_4.1.024.exe has an export directory, but does NOT export any symbols: both the numbers of names and functions are 0, and the RVAs of the functions, names and ordinals arrays are 0 too. Timeline: ========= 2018-03-28 sent vulnerability report to <secure@intel.com> no reply, not even an acknowledgement of receipt 2018-04-05 resent vulnerability report to <secure@intel.com>, CC: to CERT/CC no reply, not even an acknowledgement of receipt 2018-05-03 resent vulnerability report via HackerOne 2018-05-04 Intel acknowledges receipt 2018-05-17 Intel confirms the reported vulnerabilities 2018-05-21 Intel publishes fixed installers, with a dangling reference to SA-00140 in the release notes, plus inaccuracies regarding the dependencies of IPDT NO notification sent to me that fixes have been published! 2018-06-05 sent report about the errors in the release notes after stumbling over the fixes 2018-06-12 Intel acknowledges the report regarding the notes 2018-06-27 Intel publishes their advisory SA-00140 AGAIN no notification sent that the advisory has been published! Intel's understanding of coordinated disclosure looks rather weird to me

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

local

TYPE

permissions and access control issues

CONFIGURATIONS

EXPLOIT AVAILABILITY

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Stefan Kanthak

SOURCES

LAST UPDATE DATE

2024-11-23T21:52:57.370000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE