Malicious PDF — malware analysis report

Static analysis result for SHA-256 71d40b358867bd51…

MALICIOUS

PDF

93.2 KB Created: 2021-09-17 13:35:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: edc1a3d7a99be304e6c393fc5f346b4a SHA-1: bbc5c753b4aec729c95b0fe8f7cda1de5ed6a61d SHA-256: 71d40b358867bd513335a09b849dcd9e45078f08a0bf031d17dc44345a787c98
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised or disposable hosting, suggesting an attempt to lure users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but containing embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://rockycheng.com/ckfinder/userfiles/files/vakajemoxop.pdf In PDF document text
    • https://ntc-container.com/upload/files/lusapinikekepanesojufuvir.pdfIn PDF document text
    • http://maximaviajes.com/FCKfiles/file/zurezazanupekopozezuwi.pdfIn PDF document text
    • http://frutapac.es/ckfinder/userfiles/files/jojawepaw.pdfIn PDF document text
    • http://truhlarstvi-strakonice.cz/files/file/13459707376.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/guwuwuwofotu.pdfIn PDF document text
    • https://goooinggroup.com/userfiles/files/20210903_023422.pdfIn PDF document text
    • http://dolinakrzeptowa.pl/public/upload/ckfinder/userfiles/files/nologitizofizoxisefave.pdfIn PDF document text
    • http://sportsclinicwest.ie/media/contents/file/41267694797.pdfIn PDF document text
    • https://aluminiosarla.com/userfiles_arla/files/rodibekuramokolix.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/161420c693e0b8---82580258127.pdfIn PDF document text
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/ptvjrgq18gso9ohbu16ijuv5c0/27651992419.pdfIn PDF document text
    • http://innovad-ltd.com/userfiles/file/lipetilul.pdfIn PDF document text
    • https://dalton-english.com/userfiles/file/nakujusudusamet.pdfIn PDF document text
    • http://dkmmotor.com/files/userfiles/file/sijegepaluk.pdfIn PDF document text
    • http://vtaky.sk/media/file/74046002818.pdfIn PDF document text
    • https://marikakozmetika.hu/editor_up/juwazoxesukoz.pdfIn PDF document text
    • https://falconshipping-uae.com/userfiles/files/mobodupovex.pdfIn PDF document text
    • http://sea-cruise.ru/ckfinder/userfiles/files/tilomabe.pdfIn PDF document text
    • http://juditphotography.com/picture/userfiles/file/vigazemudadujavonizinu.pdfIn PDF document text
    • http://kripasec.com/userfiles/file/daxir.pdfIn PDF document text
    • http://geologocarmignani.com/userfiles/files/kepikepexupixo.pdfIn PDF document text
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16133172465d12---1947648429.pdfIn PDF document text
    • http://frutapacargentina.com/ckfinder/userfiles/files/sibonexefulomemukujizal.pdfIn PDF document text
    • http://rulife.ru/ckfinder/userfiles/files/76008365081.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=how+to+play+pokemon+ruby+on+androidPDF 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_off0000fba6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBA6 10908 bytes
SHA-256: f72283e25696eed3ab1b9a3ade60a1aceb1f622212dc23774eea9554287eaf2c
font_01_sfnt_off0001149e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1149E 22268 bytes
SHA-256: 128dc7e109686b5b2d4e552223e361388a0bcf80110fccb89ff0aba8ee9aed18
font_02_sfnt_off00014efc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14EFC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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