Malicious PDF — malware analysis report

Static analysis result for SHA-256 b104ff824ac345dc…

MALICIOUS

PDF

686.4 KB Created: 2014-01-29 11:47:06 -03:00 Authoring application: doPDF Ver 7.2 Build 370 (Windows 7 Business Edition (SP 1) - Version: 6.1.7601 (x64))
MD5: f3ec81fb9fbf2e9a4dce22197e90d900 SHA-1: 81be6571b0e1a9a4e3dbd5b1ecab017324df407d SHA-256: b104ff824ac345dce86c7d3fc37d08737c8ec88fe157e7fbaf3fdc8b64f1169c
514 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.003 Windows Command Shell T1105 Ingress Tool Transfer T1566.002 Spearphishing Attachment

The PDF contains embedded JavaScript that triggers a launch action, specifically targeting cmd.exe. This action is designed to execute a payload, which is an embedded Windows executable masquerading as a PDF file named 'apostila.pdf'. The embedded executable was detected by ClamAV as 'Win.Trojan.Swrort-5710536-0', and the PDF itself was flagged as 'Pdf.Tool.Agent-1388586'. This indicates a clear attempt to deliver and execute a secondary malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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\\apostila.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.Tool.Agent-1388586 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Tool.Agent-1388586
  • 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 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
apostila.pdf
1ad403ebaed2c1f39c1d61795dba3a5c0fa7b7233868feb967163cfac63a6e08		 pdf-embedded-file PDF EmbeddedFile object 309 at offset 0xA0779 73802 bytes
Detection
ClamAV: Win.Trojan.Swrort-5710536-0
Obfuscation or payload: unlikely
javascript_obj0310_000.js
fc067eb948dda7d686c1f1c801878de7c704961d33d470c5d4c92a117f714f0b		 pdf-javascript-stream PDF /JS object 310 at offset 0xAB397 57 bytes
font_00_sfnt_off0006b8db.bin
8c8b35afe61df2329519f63cf33292e30d53d13f624ea73fe5bd68776a3788d5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6B8DB 250813 bytes
font_02_sfnt_off000943ab.bin
b6c173e6d70e2537d1dde0c3f524f65208350b581b35af2fda985d5d60b5a9b0		 pdf-font-stream PDF embedded font (sfnt) at offset 0x943AB 15610 bytes
font_03_sfnt_off00098fa9.bin
62ce17f19a9bc6cc6fe978efc0f0d34b2b29e456bce82323fdf7aa90c4a60939		 pdf-font-stream PDF embedded font (sfnt) at offset 0x98FA9 13797 bytes
font_04_sfnt_off0009c727.bin
406dffb088713cd56d5f37e5d70857ae2b7f43c4246f22be37e92b14d3882e33		 pdf-font-stream PDF embedded font (sfnt) at offset 0x9C727 15750 bytes

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