Malicious PDF — malware analysis report

Static analysis result for SHA-256 c9821a1f9fd375df…

MALICIOUS

PDF

81.8 KB Created: 2021-09-11 20:08:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 0df7cb02be6857d2afbde815d6d4987d SHA-1: fa78c9af805709f958a7ed08354470b2e5076d49 SHA-256: c9821a1f9fd375dfe08e6e4bacf16b4487008e647317b41f497391d73f4ce78e
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically indicating phishing and trojan activity. Heuristics identified it as a link farm pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious sites. The document body was unreadable, but the presence of numerous URLs and the heuristic findings strongly indicate a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://emenu.hu/editor_up/30951165636.pdf In PDF document text
    • http://archinfo.ru/uploads/file/neriduwozajilenufupe.pdfIn PDF document text
    • https://clickbox.ro/images/file/13943142312.pdfIn PDF document text
    • https://daynexweb.com/upload/ckfinder/files/25433917558.pdfIn PDF document text
    • http://receptlap.hu/files/zokigagogisexebepotumazi.pdfIn PDF document text
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613b819e466b7---dorugadijogelam.pdfIn PDF document text
    • http://mingmitrcoffee.com/user_img/files/40005110911.pdfIn PDF document text
    • http://dmkaudit.sk/101/upload/file/96772303590.pdfIn PDF document text
    • http://commissioncollectionlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/54230457166.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613a9eee2a9f4---zejezojo.pdfIn PDF document text
    • http://exmar.it/foto_fck/file/75319814646.pdfIn PDF document text
    • http://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b9c63d91d0---51439115043.pdfIn PDF document text
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/161314db77e8bc---84319367081.pdfIn PDF document text
    • https://artofsurfing.com/preview/ckfinder/userfiles/files/rogex.pdfIn PDF document text
    • https://korvioinfotech.com/ckfinder/userfiles/files/17682616867.pdfIn PDF document text
    • https://035620126.tw/upload/greenkitchen/files/nogozapedudetuxesax.pdfIn PDF document text
    • http://radio-salsa.com/php/rs/filesupload/file/tagifebuditerulex.pdfIn PDF document text
    • https://starfoil-mail.nl/uploads/wysiwyg/72775950086.pdfIn PDF document text
    • https://schmitz.cz/res/file/romig.pdfIn PDF document text
    • https://shriramsteels.in/public/ckfinder/userfiles/files/68530963207.pdfIn PDF document text
    • http://cyc.cz/pictures/clanky/files/18447223102.pdfIn PDF document text
    • http://www.ags-sib.ru/ckfinder/userfiles/files/vikuvi.pdfIn PDF document text
    • http://jilienjrubin.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/nivatujuxuwenefebosiwovo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=how+hard+is+android+developmentPDF 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_off0000d9c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9C0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f1d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1D2 17916 bytes
SHA-256: 4ead432f36af8a7ef6bbeab86c5747ef546df0040e1f929667be27ffa0d9a28e
font_02_sfnt_off000120bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120BB 10800 bytes
SHA-256: 501aa1760b97d4257b290b413984f7be15860047916dd7481685b36e781f7f46