CVE-2017-0569 : Détail

CVE-2017-0569

7
/
Haute
0.26%V3
Local
2017-04-07
20h00 +00:00
2017-08-15
07h57 +00:00
CVE.org
NVD
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Descriptions du CVE

An elevation of privilege vulnerability in the Broadcom Wi-Fi driver could enable a local malicious application to execute arbitrary code within the context of the kernel. This issue is rated as High because it first requires compromising a privileged process. Product: Android. Versions: Kernel-3.10, Kernel-3.18. Android ID: A-34198729. References: B-RB#110666.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-131 Incorrect Calculation of Buffer Size
The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 7 HIGH CVSS:3.0/AV:L/AC:H/PR:N/UI:R/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.

High

A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected.

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 to carry out an attack.

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.

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

 [email protected]
V2 7.6 AV:N/AC:H/Au:N/C:C/I:C/A:C [email protected]

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 41808

Date de publication : 2017-04-03 22h00 +00:00
Auteur : Google Security Research
EDB Vérifié : Yes

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1061 Broadcom produces Wi-Fi HardMAC SoCs which are used to handle the PHY and MAC layer processing. These chips are present in both mobile devices and Wi-Fi routers, and are capable of handling many Wi-Fi related events without delegating to the host OS. On Android devices, the "bcmdhd" driver is used in order to communicate with the Wi-Fi SoC (also referred to as "dongle"). When the dongle wishes to notify the host OS of an event, it does so by encoding a special "packet" and transmitting it to the host. These packets have an ether type of 0x886C (referred to as ETHER_TYPE_BRCM), and do not contain actual packet data, but rather encapsulate information about events which must be handled by the driver. After reading packets from the SDIO interface, the "bcmdhd" driver calls the function "dhd_rx_frame" to handle each of the received frames. If a frame has the special Broadcom ether type, it is passed on to an internal handling function, "dhd_wl_host_event". This function inspects the event code, and passes it onto the registered handlers for the given event type. The function "wl_notify_gscan_event" is the registered handler for events of the following types: -WLC_E_PFN_BEST_BATCHING -WLC_E_PFN_SCAN_COMPLETE -WLC_E_PFN_GSCAN_FULL_RESULT -WLC_E_PFN_SWC -WLC_E_PFN_BSSID_NET_FOUND -WLC_E_PFN_BSSID_NET_LOST -WLC_E_PFN_SSID_EXT -WLC_E_GAS_FRAGMENT_RX (for reference, see "wl_init_event_handler") Specifically, when the event code "WLC_E_PFN_SWC" is received, the gscan handler function calls "dhd_handle_swc_evt" in order to process the event's data, like so: 1. void * dhd_handle_swc_evt(dhd_pub_t *dhd, const void *event_data, int *send_evt_bytes) 2. { 3. ... 4. wl_pfn_swc_results_t *results = (wl_pfn_swc_results_t *)event_data; 5. ... 6. gscan_params = &(_pno_state->pno_params_arr[INDEX_OF_GSCAN_PARAMS].params_gscan); 7. ... 8. if (!params->results_rxed_so_far) { 9. if (!params->change_array) { 10. params->change_array = (wl_pfn_significant_net_t *) 11. kmalloc(sizeof(wl_pfn_significant_net_t) * results->total_count, GFP_KERNEL); 12. ... 13. } 14. } 15. ... 16. change_array = &params->change_array[params->results_rxed_so_far]; 17. memcpy(change_array, results->list, sizeof(wl_pfn_significant_net_t) * results->pkt_count); 18. params->results_rxed_so_far += results->pkt_count; 19. ... 20. } (where "event_data" is the arbitrary data encapsulated in the event passed in from the dongle) When the function above is first invoked, the value of "params->change_array" is NULL. An attacker controlling the dongle may send a crafted WLC_E_PFN_SWC event, with the following values: - results->total_count = SMALL_VALUE - result->pkt_count = LARGE_VALUE Since the function fails to verify that "pkt_count" is not larger than "total_count", this would cause the allocated buffer (lines 10-11) to be smaller than the size used in the memcpy operation (line 17), thus overflowing the buffer. I've been able to statically verify these issues on the "bcmdhd-3.10" driver, and in the corresponding "bcmdhd" driver on the Nexus 6P's kernel (angler). Adding sample EtherType exploit which achieves kernel code execution on the Nexus 5. This exploit uses scapy-fakeap to broadcast a dummy network. The exploit starts the attack once a client with the target MAC connects to the network and sends an ARP request. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/41808.zip

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version 3.10

Linux>>Linux_kernel >> Version 3.18

Références

http://www.securityfocus.com/bid/97331
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/41808/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1038201
Tags : vdb-entry, x_refsource_SECTRACK