* So we work backwards from the end of the decompressed image. +++ -232,7 +232,7 static void handle_relocations(void *output, unsigned long output_len) Using a long to avoid wrapping and miscalculating the relocation.ġ file changed, 1 insertion(+), 1 deletion(-)ĭiff -git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c Situations like kexec, netboot, etc), this offset needs to be calculated This is sufficient for calculating the physicalĪddress of the relocs entry on 32-bit systems and on 64-bit systems when When processing the relocation table, the offset used to calculate the ` (4 subsequent siblings) 5 siblings, 1 reply 22+ messages in threadĬc: Kees Cook, Baoquan He, Ingo Molnar, Yinghai Lu, H. 0:09 ` x86/boot: Move compressed kernel to end of decompression buffer Kees Cook 8:02 ` x86/KASLR: Handle kernel relocations above 2G correctly tip-bot for Baoquan He 0:09 x86/boot: Improve compressed kernel handling Kees 0:09 ` Kees Cook * x86/KASLR: Handle kernel relocation above 2G The patch series following this one will split the KASLR physical Run size calculation, and (using the now available offset constants) Positioned for decompression, corrects (and simplies) the total kernel This fixes a bug (for when relocation can beĪbove 2G in later patches), standardizes where the compressed kernel is This is the next batch of patches for cleaning up x86 boot to prepareįor KASLR improvements. Peter Anvin,īorislav Petkov, Vivek Goyal, Andy Lutomirski, llin, ` (5 more replies) 0 siblings, 6 replies 22+ messages in threadĬc: Kees Cook, Ingo Molnar, Baoquan He, Yinghai Lu, H. 0:09 ` x86/KASLR: Handle kernel relocation above 2G Kees Cook This will permanently set the environment variable DOCS, but in order to use use it you need to first start a new cmd shell, then the variable is defined and ready to use: F:test>echo DOCS C:UsersDavidPostillDocuments. ![]() There you go, you’ve got system.X86/boot: Improve compressed kernel handling All of help / color / mirror / Atom feed * x86/boot: Improve compressed kernel handling 0:09 Kees Cook If these techniques fail, generate an executable for your payload and use sc or at to run it as SYSTEM. ![]() All of these techniques rely on your ability, as a privileged user, to create or inject into a service. You can always fall back to getting system by hand. On the bright side, it does not require spawning a new process and it takes place entirely in memory. This technique’s implementation limits itself to x86 environments only. When run, elevator.dll gets the SYSTEM token, opens the primary thread in Meterpreter, and tries to apply the SYSTEM token to it. This technique also passes the current thread id (from Meterpreter) to elevator.dll. It uses reflective DLL injection to run its elevator.dll in the memory space of the service it finds. It loops through all open services to find one that is running as SYSTEM and that you have permissions to inject into. This technique assumes you have SeDebugPrivileges-something getprivs can help with. If you’re worried about anti-virus or leaving forensic evidence, I’d avoid getsystem –t 0 (which tries every technique) and I’d avoid getsystem –t 2. This is an opportunity for an anti-virus product to catch you. Look at elevate_via_service_namedpipe2 in Meterpreter’s source to see this technique.Īs the help information states, this technique drops a file to disk. The DLL connects to the named pipe and that’s it. To create a client with the SYSTEM user context, this technique drops a DLL to disk(!) and schedules rundll32.exe as a service to run the DLL as SYSTEM. It creates a named pipe and impersonates the security context of the first client to connect to it. The context of the service is SYSTEM, so when you impersonate it, you become SYSTEM. Impersonation of clients is a named pipes feature. When the spawned cmd.exe connects to Meterpreter’s named pipe, Meterpreter has the opportunity to impersonate that security context. It also creates and runs a service that runs cmd.exe /c echo “some data” >\\.\pipe\. Technique 1 creates a named pipe from Meterpreter. (Default to '0').ġ : Service - Named Pipe Impersonation (In Memory/Admin)Ģ : Service - Named Pipe Impersonation (Dropper/Admin)ģ : Service - Token Duplication (In Memory/Admin) meterpreter & gt getsystem -hĪttempt to elevate your privilege to that of local system. The last one relies on token duplication. The first two rely on named pipe impersonation. The getsystem command has three techniques. ![]() Type getsystem and magically Meterpreter elevates you from a local administrator to the SYSTEM user. Meterpreter’s getsystem command is taken for granted.
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