Malicious PDF — malware analysis report

Static analysis result for SHA-256 da55407e45921fa4…

MALICIOUS

PDF

82.2 KB Created: 2017-11-25 04:27:42 UTC Authoring application: Writer (via LibreOffice 5.4)
MD5: 3cff6f2b6f51a5e1f33b16a718fb1236 SHA-1: f92a2c5150bb6684fbf0eb0c9ef8e75569725080 SHA-256: da55407e45921fa44ddbd302f87ade9f367604d27703fe62a6466f692b638922
514 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.003 Windows Command Shell T1105 Ingress Tool Transfer T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information

The PDF contains JavaScript and a launch action designed to execute cmd.exe. This command is used to drop and execute an embedded Windows executable, disguised as 'Me.pdf'. The embedded executable was detected by ClamAV as Win.Trojan.MSShellcode-7, indicating it's a malicious payload. The combination of PDF launch actions, embedded executables, and JavaScript points to a dropper or downloader functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 11

  • Adobe Reader Launch action command execution critical CVE exact CVE_2010_1240
    PDF uses the Adobe Reader/Acrobat Launch action pattern associated with CVE-2010-1240: cmd.exe is invoked with attacker-controlled parameters, paired with an embedded/exported payload.
  • Launch action critical PDF_LAUNCH
    PDF contains a /Launch action whose target is an executable, URL, or UNC path — can start an external application
  • Embedded Windows executable payload in PDF stream critical PDF_EMBEDDED_PE_PAYLOAD
    PDF stream bytes contain an embedded Windows executable with a verified PE header. Exploit chains often hide droppers inside ordinary streams rather than standard /EmbeddedFile attachments.
  • /Launch action target: cmd.exe critical PDF_LAUNCH_COMMAND
    PDF /Launch action specifies an executable target with parameters '/Q /C %HOMEDRIVE%&cd %HOMEPATH%&(if exist "Desktop\\Me.pdf" (cd "Desktop"' — references a known-dangerous executable (cmd, PowerShell, etc.).
  • Embedded attachment masquerades: declared document, content is windows-executable critical PDF_EMBEDDED_FILESPEC_CONTENT_MISMATCH
    An /EmbeddedFile attachment's declared filename extension or /Subtype MIME type contradicts the magic bytes of its decompressed content. The attachment is declared as a benign document or image but the bytes are an executable or executable-bearing archive. This is a deliberate deception used to hide droppers in PDF attachments and is a generic indicator of embed-and-drop weaponisation, independent of any specific CVE.
  • ClamAV: Pdf.Dropper.Agent-7311580-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7311580-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • /Launch action paired with attachment-dropping JS API high PDF_LAUNCH_PLUS_DROPPER_JS
    PDF combines a /Launch action with a JavaScript API call that writes or opens an attached/external resource — the canonical shape of the CVE-2010-1240 /Launch + exportDataObject family. Benign PDFs do not pair these surfaces; the combination indicates a drop-and-execute chain regardless of the specific JS API knobs or /Launch target.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
Me.pdf
a09ff57bd3abf37c5593f696c0090147c333fa28457121723c4b22bec4942e64		 pdf-embedded-file PDF EmbeddedFile object 36 at offset 0x97F3 73802 bytes
Detection
ClamAV: Win.Trojan.MSShellcode-7
Obfuscation or payload: unlikely
javascript_obj0037_000.js
5b57d88da8d1f8e2fd6da513e3728c29644ed95400196859410520697a204194		 pdf-javascript-stream PDF /JS object 37 at offset 0x14440 51 bytes
font_00_sfnt_off00002aa2.bin
fc037ca35ccbfcfdb3d4a3b46f9dd0713b141d92e70502af59411d4d6a7b83f3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x2AA2 21892 bytes
font_01_sfnt_off00004f46.bin
b9f6edc4ed1ddea87e57d63181197b63867912d734080ff33c7ea8071481acb5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x4F46 28748 bytes

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