Exploit the possiblities

Windows Attachment Manager Incorrect High Risk JAR Handling

Windows Attachment Manager Incorrect High Risk JAR Handling
Posted Oct 27, 2017
Authored by Stevie Lamb

The Windows Attachment Manager does not correctly handle JAR files marked as high risk when accessed via Internet Explorer 11.

tags | advisory
systems | windows
MD5 | 0a2b101ba0ba57f6c9393f4be248261b

Windows Attachment Manager Incorrect High Risk JAR Handling

Change Mirror Download
Scenario:

The Windows Attachment Manager does not correctly handle JAR files marked as
"high risk" when accessed via Internet Explorer 11.

This leads to direct execution of any JAR file when a user clicks "Open"
rather than "Save" or "Save as", when the expected behaviour would be a nag
dialog.



Other files added to the same "high risk" category behave as expected,
regardless of whether they are directly launched or first saved.

Currently neither Chrome, Edge nor Firefox browsers provide an "Open" option
for such files, and so are unaffected.



With some social engineering this behaviour may be exploited to gain code
execution at the privilege level of the affected user.

This is most likely to be successful when the user has been conditioned to
expect warnings from the Attachment Manager about potentially unsafe files.



MS Security decided this wasn't a security issue and by their published
definitions I accept that assertion.

But sharing's caring, this issue can and therefore probably will be abused,
if it hasn't already.



To reproduce:



Client OS : Windows 10 Pro (version 10.0.14393)

Browser : IE11 (version 11.00.14393.0) *supplied with OS for backwards
compatibility



Sample Attachment Manager configuration


Setting

State

Attribute : Value


Trust logic for file attachments

Enabled

Determine risk by : Preferring the file handler


Default risk level for file attachments

Enabled

Set the default risk level : High risk


Inclusion list for high-risk file types

Enabled

.com;.bat;.exe;.pif;.scr;.msi;.ps1;.jar;.sh;.py;.Zip;.Rar;.7z;.gz;.tar;.vbs;
.js;.wsf


Inclusion list for low file types

Enabled



Inclusion list for moderate risk file types

Enabled

.doc;.xlsx;.docx;



1. Download any JAR file using the built-in IE11 (x64 or x86) and opt
to open it.

2. The file opens without any nag dialog indicating the file type is
potentially harmful.



Hope it's useful.

Kind regards,
Stevie

Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

Want To Donate?


Bitcoin: 18PFeCVLwpmaBuQqd5xAYZ8bZdvbyEWMmU

File Archive:

January 2018

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Jan 1st
    2 Files
  • 2
    Jan 2nd
    13 Files
  • 3
    Jan 3rd
    16 Files
  • 4
    Jan 4th
    39 Files
  • 5
    Jan 5th
    26 Files
  • 6
    Jan 6th
    40 Files
  • 7
    Jan 7th
    2 Files
  • 8
    Jan 8th
    16 Files
  • 9
    Jan 9th
    25 Files
  • 10
    Jan 10th
    28 Files
  • 11
    Jan 11th
    44 Files
  • 12
    Jan 12th
    32 Files
  • 13
    Jan 13th
    2 Files
  • 14
    Jan 14th
    4 Files
  • 15
    Jan 15th
    31 Files
  • 16
    Jan 16th
    15 Files
  • 17
    Jan 17th
    16 Files
  • 18
    Jan 18th
    24 Files
  • 19
    Jan 19th
    15 Files
  • 20
    Jan 20th
    5 Files
  • 21
    Jan 21st
    1 Files
  • 22
    Jan 22nd
    15 Files
  • 23
    Jan 23rd
    17 Files
  • 24
    Jan 24th
    35 Files
  • 25
    Jan 25th
    0 Files
  • 26
    Jan 26th
    0 Files
  • 27
    Jan 27th
    0 Files
  • 28
    Jan 28th
    0 Files
  • 29
    Jan 29th
    0 Files
  • 30
    Jan 30th
    0 Files
  • 31
    Jan 31st
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2018 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close