Malicious PDF — malware analysis report

Static analysis result for SHA-256 21eca943f8e95a08…

MALICIOUS

PDF

96.3 KB Created: 2021-06-30 10:59:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 49729a48e9e2f0176582f8ee12b3e9ed SHA-1: 64daf3e2049a1985c8679883074b9c924b2e6b80 SHA-256: 21eca943f8e95a08ff88ef710ed2c266b1992d9b035ab63ec4284bb7deba84f8
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress sites utilizing form plugins for file uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable, but the heuristic firings and URL analysis confirm its function as a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://www.focus.mu/wp-content/plugins/super-forms/uploads/php/files/b23fa0b9f423d601bd34be9c029f7c3a/74176228148.pdf In PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ce4b03852ac---82201646982.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a05e6c66e4a---dirifu.pdfIn PDF document text
    • https://palcev.ru/userfiles/file/4584642277.pdfIn PDF document text
    • http://cricalliance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160771fca2b51c---xefajuxuxemeto.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607594d3ac2de---980993369.pdfIn PDF document text
    • https://alajuusa.ee/media/contents/file/zojagosawaximerivapobaweb.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/160883a8b81a14---rodixewabojuja.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606c911c9bd87---68211359367.pdfIn PDF document text
    • https://ifacemount.com/wp-content/plugins/super-forms/uploads/php/files/guls9h4ob8321f2mnu2jtsmvng/lidadovufoj.pdfIn PDF document text
    • http://hurtmar.pl/Upload/file/712170002.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/cfotmoj9r8aajpoi802it6rtqb/27821347714.pdfIn PDF document text
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/ht8p9i8tdahpb5e6k6g58g3dpt/92676890026.pdfIn PDF document text
    • http://lycee-elm.org/userfiles/file/pegimawitideku.pdfIn PDF document text
    • http://dnepropress.net/files/file/xurulakomopapixoninomuj.pdfIn PDF document text
    • https://abhimaninteriors.com/ckfinder/userfiles/files/visizejunojolasebin.pdfIn PDF document text
    • https://stallion-international.com/userfiles/file/denobufikenijawokivipub.pdfIn PDF document text
    • http://alarmy-kamery24.pl/userfiles/file/92909489867.pdfIn PDF document text
    • http://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a5ad0cc30ef---vusiparajam.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/zaxukokuxa.pdfIn PDF document text
    • https://www.accidentinjurylascruces.com/wp-content/plugins/super-forms/uploads/php/files/l1dbgkui1et9i72vc6u3sjlvka/39982895711.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=the+woods+are+lovely+dark+and+deep+which+poemPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001151e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1151E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012d30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D30 17348 bytes
SHA-256: b4d7206ab52bc99a947d4f5b208286117c01fc3f0dbf7aabd0f18dc9b98efee2
font_02_sfnt_off00015a57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15A57 11004 bytes
SHA-256: f1d1f57179139835954af63f7388ef050573738175b21f2b5f5467a4f54adb53