Malicious PDF — malware analysis report

Static analysis result for SHA-256 f51981ce7187513d…

MALICIOUS

PDF

81.9 KB Created: 2021-09-06 10:53:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: e6fb0cc74e00197506cfb44c39e83069 SHA-1: cc98a40d74f4e1cb5c48b106178779fa628be070 SHA-256: f51981ce7187513db5a67d9f354784b24b8fdc1b4be4a15c40991ee8a3eed760
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to potentially compromised websites or disposable hosting, indicating a link farm or redirection scheme. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution. No scripts were extracted, and the document body was unreadable, so the primary attack vector appears to be the exploitation of PDF vulnerabilities or social engineering through the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://medtek.vn/storage/file/77707715154.pdf In PDF document text
    • http://szkolka-wiercioch.pl/files/file/xikij.pdfIn PDF document text
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609154be69d6f---rexevunofitakem.pdfIn PDF document text
    • http://www.mousumibanerjee.com/fckimages/file/42652107996.pdfIn PDF document text
    • https://betentour.com/sites/default/files/file/8146570455.pdfIn PDF document text
    • http://goreskyreunion.com/clients/b/ba/ba087d28c24afe6c5bc45fa062332e47/File/dixatotomuwubaguwejuwu.pdfIn PDF document text
    • https://rosycaffe.com/file/93665525848.pdfIn PDF document text
    • http://korvet-sp.ru/userfiles/file/17252798942.pdfIn PDF document text
    • http://www.centralperdana.com/file/jodevikirizaniji.pdfIn PDF document text
    • https://uleshuzataruhaz.hu/files/file/82806977396.pdfIn PDF document text
    • http://punaide.com/userfiles/files/625333069.pdfIn PDF document text
    • https://9ja-bet.com/userfiles/file/2587426336.pdfIn PDF document text
    • https://pnp-studio.com/fckeditorfiles/file/zerisiraja.pdfIn PDF document text
    • http://amazingindiaphotos.com/amazingindiaphotos//upload/fckimage/file/xojazumazalare.pdfIn PDF document text
    • http://jkohut.pl/file/bokixomafikitunorar.pdfIn PDF document text
    • https://www.highlandernepal.com/assets/ckfinder/userfiles/files/libofotijunebobuwefi.pdfIn PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/18489132493.pdfIn PDF document text
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf5cdaea351---zutoribomereredupaberi.pdfIn PDF document text
    • http://likebarcode.com/image/files/20210812_150109.pdfIn PDF document text
    • https://rpdev.org/ckfinder/userfiles/files/luwilapesorufonutapax.pdfIn PDF document text
    • https://christembassyromford.org/wp-content/plugins/super-forms/uploads/php/files/cc43638b8124d9382e230ffd70fa2163/ranasisob.pdfIn PDF document text
    • http://dostavkaturov.ru/files/file/pazuzamanad.pdfIn PDF document text
    • http://yjsyrj.com/userfiles/file/62531870574.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=milling+machine+pdf+booksPDF 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_off0000dc6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC6C 17168 bytes
SHA-256: 07ec67e4af4d25b593bb7ab47de9a59ff7e9c6e6eb74767be39af9138f8952b9
font_01_sfnt_off000108c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108C9 11092 bytes
SHA-256: 67a7398e797f3a5a8cb0e1ad5a4542f70b513a23c66fc5c4f8a645663f4161e2
font_02_sfnt_off000121fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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