Reverse Engineering Stack Exchange is a question and answer site for researchers and developers who explore the principles of a system through analysis of its structure, function, and operation. It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. There is malicious functionality in the DLL referenced by the registry key but this malware sample does not load or call the DLL, nor does it exhibit any other malicious behavior.
Basically, all DLLs listed in that reg-key are loaded when any process is started. All the DLLs that are specified in this value are loaded by each Microsoft Windows-based application that is running in the current log on session. They are usually used by malicious code tho it doesn't have to be malicious as a way of DLL injection, to hook functions for example.
The actual registry path differs between 64bit and 32bit version of OS. Multiple entries are split with space or comma, and the path to the DLL must not contain any spaces for obvious reasons.
In user So by setting this registry key, the malware dll will be injected into every process started after setting this key. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Sign in. United States English. Ask a question.
Quick access. Search related threads. Remove From My Forums. Answered by:. Archived Forums. Group Policy. Sign in to vote. Note that disabling or deleting an autostart entry prevents it from being automatically started in the future. Also note that if you disable autostarts that are critical for system boot, initialization, or correct operation, you can put the system into a state in which recovery is not possible without booting into an alternate operating system or recovery environment.
On some versions of Windows, the registry keys containing configuration information for some services are locked down, and many scheduled tasks are not standard-user readable. But for the most part, Autoruns works perfectly fine without administrative rights for the purposes of viewing autostart entries.
If you select or clear a check box, or try to delete one of these entries without administrative rights, Autoruns will report Access Denied. The error message dialog box includes a Run As Administrator button that lets you restart Autoruns elevated. See Figure When Autoruns has administrative rights, configuration changes should succeed. To ensure that Autoruns has elevated rights when it launches, start Autoruns with the —e command-line option.
This will request UAC elevation if the invoker is not already running elevated. Therefore, seeing that text in the Publisher column gives only a low degree of assurance that the file in question was created by Microsoft and has not been modified since. The file format for some types of files allows for a digital signature to be embedded within the file. Catalog signing means that even plain text files can be verified. Instead of verifying entries one at a time, you can enable Verify Code Signatures in the Scan Options dialog box and rescan.
Autoruns will then attempt to verify the signatures for all image paths as it scans autostarts. Note that the scan might take longer because it also verifies whether each signing certificate has been revoked by its issuer, which requires Internet connectivity to work reliably. Files for which signature checks fail might be considered suspicious and therefore appear in pink. A common malware technique is to install files that on casual inspection appear to be legitimate Windows files but are not signed by Microsoft.
VirusTotal also offers an API for programs such as Autoruns that makes it possible not only to scan many files at once, but also to do so much more efficiently by uploading only file hashes rather than entire files. If VirusTotal has recently received a file with the same hash, it returns the results from the most recent scan rather than performing the scan again.
You can analyze all autostart entries by enabling Check VirusTotal. Autoruns uploads file hashes to VirusTotal.
As results come back, Autoruns replaces the text in that column with the number of engines that flagged the file out of the total number of engines that returned results, rendered as a hyperlink, as shown in Figure As an additional visual indicator, the link is colored red if any engines flagged the file as suspicious.
Click the link to open the webpage where you can see details of the results. Click that link to view the progress of the analysis. You can also analyze items one at a time by right-clicking an autostart and choosing Check VirusTotal from the popup menu.
On first use of VirusTotal, Autoruns will open your default web browser to the VirusTotal terms of service page and prompt you in a message box to agree with the terms before proceeding. None of these options requires rescanning the system; they manipulate the previously-collected results and can show hidden entries again instantly on demand.
The Hide Windows Entries option is enabled by default. If the entry is a hosting process such as Cmd. The behavior of these two options depends on whether Verify Code Signatures is also enabled. As mentioned earlier, it is easy for anyone to create a program that gets past this check, so the Verify Code Signatures option is highly recommended.
If signature verification is enabled, Hide Windows Entries omits entries that are signed with the Microsoft Windows code-signing certificate. Windows components are signed with a different certificate from other Microsoft products. Hide Microsoft Entries omits entries that are signed with any Microsoft code-signing certificate that chains to a trusted root certificate authority on the computer. Consequently, these entries can be hidden when signature verification is enabled but displayed when verification is not enabled.
The SigCheck utility described in Chapter 9 reports both the Company Name and the name from the signing certificate. The AutorunsC utility described later in this chapter can report both also. On a typical system, this option should hide most entries. Note that when a small number of the VirusTotal engines report an issue, it is usually a false positive.
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