Malicious PDF — malware analysis report

Static analysis result for SHA-256 6b5579b2d24ff937…

MALICIOUS

PDF

1.14 MB Created: 2010-04-20 09:41:09 Authoring application: Microsoft® Office Word 2007
MD5: 0c9f39706bb17a906a6e0cbef93abeb5 SHA-1: c33aee002b61eeca4b10d7cd2ce0b35667b41be2 SHA-256: 6b5579b2d24ff93765790be6aeb78c9ccdb8003ad411ea37024b27d6e4ec2545
618 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that triggers a launch action, executing cmd.exe. This action is designed to export a data object named 'c:Helloworld.pdf', which is actually a Windows executable disguised as a PDF. This technique is commonly used to download and execute secondary payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 15

  • 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.
  • TrueType bitmap font + active content — CVE-2023-26369 related high CVE related PDF_CVE_2023_26369_RELATED
    PDF embeds a TrueType font with bitmap tables (EBDT/sbix/CBDT) alongside exploit delivery indicators — CVE-2023-26369 exploits the sfac_GetSbitBitmap function in Adobe's libCoolType for arbitrary code execution. This CVE was actively exploited in the wild, but this rule does not validate the malformed EBLC/EBDT primitive.
  • 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\\c:\Helloworld.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.
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ocsp.verisign.com0
    • http://nsis.sf.net/NSIS_Error
    • http://www.microsoft.com/typography/ctfontshttp://fontfabrik.comYou
    • http://www.microsoft.com/typography/fonts/default.aspx
    • http://crl.verisign.com/ThawteTimestampingCA.crl0
    • http://crl.verisign.com/tss-ca.crl0
    • http://crl.microsoft.com/pki/crl/products/CodeSignPCA2.crl0O
    • http://www.microsoft.com/pki/certs/CodeSignPCA2.crt0
    • http://www.microsoft.com/typography

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
cHelloworld.pdf
77bab76fd22ae50479186486c2fc685efaa4a75546374597c068a05d93686a45		 pdf-embedded-file PDF EmbeddedFile object 20 at offset 0xBF9C 1166966 bytes
Detection
ClamAV: Win.Trojan.Startpage-511
Obfuscation or payload: likely
Carved artifact entropy is 7.94, consistent with packed or encrypted content.
javascript_obj0021_000.js
d1e2a417a5630e6989076b3320e4f5063159b5be3531c20fae58059e3267551e		 pdf-javascript-stream PDF /JS object 21 at offset 0x123B3B 61 bytes
font_00_sfnt_off000006fa.bin
98d7a1454894f9ccb21406205b22cfc554e74c0f1b21063ab4baff0f67884395		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6FA 87808 bytes

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