apphelp.dll
Application Compatibility Client Library file version info
Library on Windows 2 known copies with hashes 2 Sigma rules name it
Is it the real apphelp.dll?
Original name
Apphelp in the file’s header: a renamed copy still carries itInstalled in
C:\Windows\system32\C:\Windows\SysWOW64\Signed byMicrosoft Windows
ProductMicrosoft Windows Operating System, Microsoft Corporation
DescriptionApplication Compatibility Client Library
2 known copies
10.0.19041.1 (WinBuild.160101.0800) · C:\Windows\SysWOW64\apphelp.dll · signed by Microsoft Windows
9ee4d74ccaf5a4d9995dafac34450fe96f0f8f13b031a5c102311afe9a8e5bf710.0.19041.1 (WinBuild.160101.0800) · C:\Windows\system32\apphelp.dll · signed by Microsoft Windows
bb93758eb2ea6ce141de22401765e281c4bad2c65d8c23e15ccf261475fb0f0bFrom the file’s version info and the copies recorded by xCyclopedia (MIT). A copy in another folder, signed by someone else or with another hash is not necessarily malicious, but it is worth a closer look. In Ceplin, "<sha256>".whatis() says which known copy a hash is.
What detects it
Sigma names apphelp.dll in 2 rules in all, for every kind of event; this is the process creation rule CmdID evaluates.