If you use Windows Task Manager to check running processes and find multiple copies of rundll32.exe, it may mean that there is a virus or Trojan on your computer. But the official Windows rundll32.exe is safe and will not harm your computer.
Note: the article describes how to run a full SFC check using the /scannow option. If you had a recent virus infection this is the best option as it checks all important Windows files so it can replace any others that are missing/corrupted, not just rundll32.exe
These directories include a backup of many system files which can be used to replace those which are corrupted or missing. In all versions of Windows except XP, you may need to search all the WinSxS subfolders (including hidden and system files) to find the backup version of rundll32.exe if it is present.
While monitoring the network activity or rundll32.exe from Austin, Texas USA with the GlassWire software we found it connects to settingsfd-geo.trafficmanager.net which appears to be controlled by Microsoft Corporation. We found no other network activity with the .exe. We believe rundll32.exe connects to settingsfd-geo.trafficmanager.net to help manage the distribution of traffic across your PCs endpoints. This traffic management seems to happen at the DNS level to help your PC and apps work properly.
The genuine rundll32.exe file is a software component of Microsoft Windows Operating System by Microsoft Corporation."RunDLL32.exe" is Microsoft's "Windows Host Process," (or, "Run a DLL as an app,") a powerful tool available since Windows Vista and Windows Server 2008. On 32-bit Windows systems, it resides in "C:\Windows\System32." On 64-bit systems, two "rundll32.exe" processes exist in "\System32" and "\SysWOW64" to call 64-bit and 32-bit DLL's respectively. In any other location this process name is probably disguised malware from trojans or viruses, especially in subfolders of the user's profile folder. Code in Dynamic Link Library (.DLL) files is not normally directly executable; it must be called from a process. Library files reduce RAM and disk usage by segmenting code loaded into active memory, and allowing multiple applications to call one copy of a commonly-used function (or "method"). Developers familiar with Windows API method names can use "rundll32.exe" commands in scripts to call specific methods within specific DLL's to perform Windows functions remotely and/or on a schedule.
The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the rundll32.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.
Description: The original rundll32.exe from Microsoft is an important part of Windows, but often causes problems. Rundll32.exe is located in the C:\Windows\System32 folder or sometimes in the C:\Windows folder.Known file sizes on Windows 10/11/7 are 33,280 bytes (33% of all occurrences), 44,544 bytes and 23 more variants. The process is the bff42538 service.Rundll32.exe is a Windows core system file. The file is a Microsoft signed file. The program is not visible.Therefore the technical security rating is 7% dangerous, but you should also take into account the user reviews.
Is rundll32.exe a virus? No, it is not. The true rundll32.exe file is a safe Microsoft Windows system process, called "Windows host process".However, writers of malware programs, such as viruses, worms, and Trojans deliberately give their processes the same file name to escape detection. Viruses with the same file name are for example WS.Reputation.1 (detected by Symantec), and Trojan-Dropper.Win32.Injector.ebsj or Trojan.Win32.Zapchast.acbp (detected by Kaspersky).To ensure that no rogue rundll32.exe is running on your PC, click here to run a Free Malware Scan.
Important: Some malware disguises itself as rundll32.exe, particularly when not located in the C:\Windows\System32 folder. Therefore, you should check the rundll32.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.
Summary: Average user rating of rundll32.exe: based on 494 votes with 9 user comments.178 users think rundll32.exe is essential for Windows or an installed application.22 users think it's probably harmless.121 users think it's neither essential nor dangerous.70 users suspect danger.103 users think rundll32.exe is dangerous and recommend removing it.77 users don't grade rundll32.exe ("not sure about it").
To help you analyze the rundll32.exe process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.
I believe that is caused by UAC and how the Admin account is subjected to UAC per say.I have done the below to resolve that.You can also create a short-cut to the area you are blocked and it worked that way for me to.Do a search on the rundll32.exe and UAC to see more info about it.
If Target contains any commas, they must be escaped as shown three times in the following example:Run rundll32.exe shell32.dll`,Control_RunDLL desk.cpl[color=#FF0000]`,`,[/color] 3 ; Opens Control Panel > Display Properties > Settings
...I see you mean just in that example.. I am removing the backquotes so it works in start..run if I click start then run then "C:\Windows\system32\rundll32.exe" sysdm.cpl,EditEnvironmentVariables it doesn't work
I am running Windows 8.1 Update in a Parallels VM. After about 5 minutes of inactivity, a rundll32.exe process is spawned and consumes a core. MsMpEng.exe activity also increases. (probably due to lots of IO but I can't confirm) If I interact with the VM in any way, the rundll32.exe immediately exits until I let it idle for another 5 minutes.
Hi I have found this same problem with updating to Win 10 and not a single common answer to this issue worked for me, when my computer would go idle the C:Drive usage would go up to 100% and make any task impossible, leading to manual shutdown by holding the power button. Windows Process explorer would show rundll32.exe and in the properties of this file would be C:\Windows\system32\rundll32.exe invagent,RunUpdate -noappraiser (then random numbers and letters).
So I have fixed 100% C:drive problem by changing invagent.dll to invagent.dll.bak. But potentially opened up a new problem that is currently not causing me any issues. I will edit this answer if I have any further issues over the next week, or discover why multiple versions of rundll32.exe are now running.
Your problem likely is that your program is compiled as 32-bit and your OS is 64-bit, and thus, when you try to access "C:\Windows\System32\Speech\SpeechUX\SpeechUX.dll" from your program, you're really accessing "C:\Windows\SysWOW64\Speech\SpeechUX\SpeechUX.dll" which, as rundll32.exe is reporting doesn't exist.
Command-line parameters are some of the most reliable telemetry for detecting malicious use of Rundll32, since adversaries often need to pass command-line arguments for Rundll32 to execute. Eight of our top 10 detection analytics for Rundll32 include a command-line component. Capturing command-line activity will capture the both name of the DLL that was launched by rundll32.exe and any additional command-line arguments.
Consider monitoring for instances of rundll32.exe running Windows native DLLs that have export functionalities that adversaries commonly leverage for executing malicious code and evading defensive controls. The following pseudo-analytic applies specifically to adversaries who use the MiniDump export functionality of comsvcs.dll to dump the contents of LSASS, but this logic could be adapted to detect other malicious activity as well.
Rundll32 does not normally execute without corresponding command-line arguments and while spawning a child process. Given this, you may want to alert on the execution of processes that appear to be rundll32.exe without any command-line arguments , especially when they spawn child processes or make network connections.
3:38:02 PMC:\windows\system32\cmd.exe /c "C:\windows\system32\rundll32.exe setupapi,InstallHinfSection DefaultUninstall 128 C:\Program Files\Splunk\bin\SplunkMonitorNoHandleDrv.inf >> "C:\Users\ADMINI~1\AppData\Local\Temp\splunk.log" 2>&1"3:38:03 PMC:\windows\system32\cmd.exe /c "C:\windows\system32\rundll32.exe setupapi,InstallHinfSection DefaultUninstall 128 C:\Program Files\Splunk\bin\splknetdrv.inf >> "C:\Users\ADMINI~1\AppData\Local\Temp\splunk.log" 2>&1"3:38:04 PMC:\windows\system32\cmd.exe /c "C:\windows\system32\rundll32.exe setupapi,InstallHinfSection DefaultUninstall 128 C:\Program Files\Splunk\bin\splunkdrv.inf >> "C:\Users\ADMINI~1\AppData\Local\Temp\splunk.log" 2>&1"3:39:05 PMC:\windows\system32\cmd.exe /c ""C:\Program Files\Splunk\bin\splunk.exe" start --answer-yes --no-prompt --accept-license --auto-ports >> "C:\Users\ADMINI~1\AppData\Local\Temp\splunk.log" 2>&1"'"C:\Program Files\Splunk\bin\splunk.exe"' is not recognized as an internal or external command,operable program or batch file. 2b1af7f3a8