Malicious PDF — malware analysis report

Static analysis result for SHA-256 3fd55e9a32900bb5…

MALICIOUS

PDF

78.6 KB Created: 2021-08-11 08:18:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-17
MD5: 11ab5823ae91320d5f60c2083e4610b2 SHA-1: ea5fe4c6c9fee91a6014eba5b212ef8a31315c8f SHA-256: 3fd55e9a32900bb5130fe9d7508173f201352bc9eedd95ded293bc839136a1c7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by ClamAV as a phishing trojan and by an ML classifier as malicious. It contains numerous external URIs, many of which point to compromised WordPress sites or disposable hosting, forming a link farm. While no explicit script content was extracted, the presence of embedded JavaScript streams and the nature of the link farm suggest an attempt to lure users to malicious sites, likely for phishing or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

Heuristics 7

  • 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.
  • 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.
  • 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.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160868d6589e00---kugopujudafixobitezime.pdf In PDF document text
    • http://abwlanham.com/uploads/files/wutefatumakuteramexewu.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/16109956e94900---14374031571.pdfIn PDF document text
    • http://costruzionibulagna.it/userfiles/files/74183019479.pdfIn PDF document text
    • http://www.rolstoellift.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ed507c3398---videsunevivavow.pdfIn PDF document text
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/9fc0f4bf41fa2e7aa702e4042e5ef65e/11462858168.pdfIn PDF document text
    • http://www.sospapa24.com/lib/ckfinder/imgupload/files/zegav.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/160912b068abfc---76340416595.pdfIn PDF document text
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce96d253b2---zunulisugal.pdfIn PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5ef4b2319b---dovosezomizegamisukajas.pdfIn PDF document text
    • https://egyiksem.hu/uploads/file/ziravukevug.pdfIn PDF document text
    • http://vietxetai.com/wp-content/plugins/super-forms/uploads/php/files/bqs4pegaj85ubh576p17v8j0kd/68135845800.pdfIn PDF document text
    • http://aostavet.it/userfiles/files/37914615907.pdfIn PDF document text
    • https://lawtutors.co.uk/js/ckfinder/userfiles/files/wagugofusevez.pdfIn PDF document text
    • http://finsura-lifedirect.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16072b2ef17382---nujixudanapomavivar.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/73db363057ef7581c5e1fbc9edd7f7a1/78980341240.pdfIn PDF document text
    • https://lexconsulting.ro/webroot/files/media/914744017.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8b82f45faf---verakiduzo.pdfIn PDF document text
    • http://tsrmmessina.it/userfiles/files/72483764609.pdfIn PDF document text
    • https://marcuspietrek.de/MARCUS/files/file/mozujejotakomenol.pdfIn PDF document text
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609485858988a---modimigumipewunetekopi.pdfIn PDF document text
    • http://tcsklife.com/filespath/files/20210809082829.pdfIn PDF document text
    • http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b613c39e96e---34578189467.pdfIn PDF document text
    • https://veritiesinstitute.com/wp-content/plugins/super-forms/uploads/php/files/5cc7134fee28c2eb0b1c6a3c1dad20a1/11997753799.pdfIn PDF document text
    • http://partnerplus30.ru/images/fornews/files/jeduwanowiloz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=examen+diagnostico+de+matematicas+para+primer+grado+de+primariaPDF 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_off0000cccc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCCC 17300 bytes
SHA-256: 35aeeb516e6f1c292c8d05254c2f471465cce5e4683ed94b48f8f91be275b4d6
font_01_sfnt_off0000f87a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF87A 10896 bytes
SHA-256: 36a18eb8e4357fb96d027891f4416ff06706444a90427dcb1bb9620e577af9f3
font_02_sfnt_off00011171.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11171 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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