Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa40c9e09592dc9f…

MALICIOUS

PDF

75.3 KB Created: 2021-08-28 05:03:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9c2d65a597b72985b8d68208d4bc2d93 SHA-1: 447cfa591833fb2cb3d15067a5ef6473aebc78c3 SHA-256: aa40c9e09592dc9f4f5d628bb548ca74c8fcfc27dec21fc0e18a297fd814d740
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous links to external websites, many of which are hosted on compromised WordPress sites or disposable domains, indicating a link farm designed to redirect users to potentially malicious content. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting the primary purpose is not informational but rather to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.putnamtaxi.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609e86f6a3d70---jalumufiwenujamubadolema.pdf
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/cjvibqrhduiqm30i9j5qnp62nj/18941060072.pdf
    • http://globalone-mould.com/gbw/fckfiles/20210815141843.pdf
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16091d429ca59b---66843457654.pdf
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/2aa4064b03bb7a8ace2c25a32f05148b/57438925867.pdf
    • http://sistersaviopublicschool.com/userfiles/file/19280126810.pdf
    • https://endoaccessories.com/wp-content/plugins/super-forms/uploads/php/files/15fckb5q49sd0o3suq8ci92pud/towawujogapetipomusunodu.pdf
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608247203d5ce---bigebisujuxemapafop.pdf
    • http://bioterapiazabiegi.pl/obrazy/file/zowobewivesufevewiwajafig.pdf
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/4f9007980dc97adf8fbb29c0681b974d/79463093325.pdf
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/33m43jk8n341m773883niq97hk/duzek.pdf
    • http://www.whirlpool-beachcomber.at/wp-content/plugins/formcraft/file-upload/server/content/files/16083aa2298efa---nefugu.pdf
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bc87d74c64a---58001440205.pdf
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/16129190a34348---wigakojegidupewopij.pdf
    • http://cezanart.com/userfiles/file/ponujuto.pdf
    • https://amitadevnani.com/userfiles/file/lulur.pdf
    • http://sireny.net/share/files/28297561837.pdf
    • https://blnk.eu/userfiles/files/kamutotizozogadiwibima.pdf
    • http://lasfyy.com/uploadfile/file/20210607045258309.pdf
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/1610e7bda2dd0e---84885260965.pdf
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/a2s7kva0n6jbt6copq1b18aa8r/sodoba.pdf
    • http://bangladeshceramicsociety.com/uploads/editor/files/4283884044.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=probation+period+employment+law
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c550.bin
a76cfd241d4c6770498c96da6b8b25f808d4d103abfabc6c4306ea3e5c01c0a0
pdf-font-stream PDF embedded font (sfnt) at offset 0xC550 10724 bytes
font_01_sfnt_off0000ddbb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDDBB 16792 bytes
font_02_sfnt_off0000f5cd.bin
0d7d05e80e544dc89a115409eeaee23c25210486e29cc7e72960f29dc51d1795
pdf-font-stream PDF embedded font (sfnt) at offset 0xF5CD 15908 bytes