PDF_CVE20184990.THEAFAH

May 17, 2018
 Analysis by: Michael Jhon Ofiaza
 ALIASES:

HEUR:Trojan.PDF.Agent.gen (Kaspersky) ; Exploit:PDF/Bedobedobe.A [non_writable_container] (Microsoft) ; Trojan.Pidief (Norton)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Exploit

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware, Propagates via software vulnerabilities

This Exploit arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It takes advantage of certain vulnerabilities.

  TECHNICAL DETAILS

File Size:

82,344 bytes

File Type:

PDF

Memory Resident:

No

Initial Samples Received Date:

15 May 2018

Payload:

Executes files, Drops files

Arrival Details

This Exploit arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Exploit drops the following files:

  • c:\Users\All Users\Start Menu\Programs\Startup\one.vbs

Other Details

This Exploit does the following:

  • If executed, one.vbs will drop and execute the following copy of calc.exe:
    • C:\Users\Public\Documents\OneNote.exe

It takes advantage of the following vulnerabilities:

NOTES:
This is the Trend Micro detection for the proof of concept (PoC) sample of CVE-2018-4990 and CVE-2018-8120. Displays the following after execution:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.254.04

FIRST VSAPI PATTERN DATE:

16 May 2018

VSAPI OPR PATTERN File:

14.255.00

VSAPI OPR PATTERN Date:

17 May 2018

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as PDF_CVE20184990.THEAFAH

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • c:\Users\All Users\Start Menu\Programs\Startup\one.vbs
  • C:\Users\Public\Documents\OneNote.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as PDF_CVE20184990.THEAFAH. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:


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