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
None
PR
The attacker is unauthenticated 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
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
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
None
I
There is no impact on the integrity of the system; the attacker does not gain the ability to modify any files or information on the target system.
Availability
None
A
There is no impact on the availability of the system; the attacker does not have the ability to disrupt access to or use of the system.
Below is a copy: Apple WLC_E_COUNTRY_CODE_CHANGED Information Leak
Apple: Information Leak when handling WLC_E_COUNTRY_CODE_CHANGED event packets
CVE-2017-7116
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 iOS, the "AppleBCMWLANBusInterfacePCIe" driver is used in order to handle the PCIe interface and low-level communication protocols with the Wi-Fi SoC (also referred to as "dongle"). Similarly, the "AppleBCMWLANCore" driver handles the high-level protocols and the Wi-Fi configuration.
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, and do not contain actual packet data, but rather encapsulate information about events which must be handled by the driver.
One of the supported event packets is the WLC_E_COUNTRY_CODE_CHANGED message, which notifies that host that the country code has been modified. On iOS, these events are handled by the "handleCountryCodeChangedEvent" function in the "AppleBCMWLANCore" driver. Each packet of this type starts with the common event message header (which is 48 bytes long), followed by the 3-character country code, delimited by a NUL.
Here is a snippet of "handleCountryCodeChangedEvent"'s high-level logic:
int64_t handleCountryCodeChangedEvent(void* this, uint8_t* event_packet) {
char* country_code = (char*)this + 3244;
char* alt_country_code = (char*)this + 3248;
strncpy(country_code, event_packet + 48, 3);
country_code[3] = '\0';
if ( strncmp(country_code, "XZ", strlen("XZ")) &&
strncmp(alt_country_code, country_code 4)) {
strncpy(alt_country_code, country_code, 3);
alt_country_code[3] = '\0';
updateChannelSpecsAsync(this);
}
...
}
int64_t updateChannelSpecsAsync(void* this)
{
char request_buffer[0x1C2];
bzero(request_buffer, 0x1C2);
char* country_code = (char*)this + 3244;
strlcpy(request_buffer, country_code, 4);
return issueCommand(..., request_buffer, ...); //Getting the "chanspecs" IO-Var
...
}
As can be seen above, the function fails to verify that the length of the event message is sufficiently long (that is, larger than just the message header itself). As a result, an attacker controlling the dongle can send a WLC_E_COUNTRY_CODE_CHANGED event packet with no body payload. Doing so will cause the 3 bytes of the country code to be copied OOB (from event_packet + 48). As long as these bytes are not "XZ" or the previously stored country code ("alt_country_code"), "updateChannelSpecsAsync" will be called, causing the OOB data to be sent back to the dongle in the WLC_GET_VAR ioctl - thus leaking the bytes back to the dongle.
This bug is subject to a 90 day disclosure deadline. After 90 days elapse
or a patch has been made broadly available, the bug report will become
visible to the public.
Found by: laginimaineb
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