Malicious PDF — malware analysis report

Static analysis result for SHA-256 36a21dedb1cba2cd…

MALICIOUS

PDF

87.2 KB Created: 2021-07-18 22:53:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a8562c8b0fc056f1d8aa41125561d5e0 SHA-1: adaba54e3de4bc3fb08f83b4289c77174a460d97 SHA-256: 36a21dedb1cba2cd1e6d732bf5ab6e5b0c303d712f1c44826a1d9d57b36d75da
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The document body was unreadable, but the presence of many external links strongly supports the link farm attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://detikakdeti.ru/img/file/demuzikolerofili.pdf
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/a37a693fd2866adb66caa5aa7e4c5e9b/57586234680.pdf
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/160e854f0d2997---79472303192.pdf
    • http://kondicionery-lubertsy.ru/upload_picture/file/nusedatafusasubov.pdf
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be1563a6d46---relipe.pdf
    • https://asset-books.com/userfiles/file/bafavidazi.pdf
    • http://airholic.com/UpFiles/WebEditorFiles/file/40919478534.pdf
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/1b7vlkq6naum9k83467fqf7qut/famakedabixir.pdf
    • https://bbpartner.cz/userfiles/file/54662012705.pdf
    • https://mebelpozakazu.ru/wp-content/plugins/super-forms/uploads/php/files/5e76f01004ab07a954c4332eed6eef92/65168873131.pdf
    • https://vickers-electronics.co.uk/wp-content/plugins/super-forms/uploads/php/files/44a510ec6969b04662b398dc8889c963/54044650006.pdf
    • http://laweasy.kr/userfiles/file/2305028820.pdf
    • https://www.cir.cloud/wp-content/plugins/formcraft/file-upload/server/content/files/160c923ca56228---28196465652.pdf
    • https://pabrikangka.com/contents//files/50254925336.pdf
    • https://floridaholidayplanner.com/wp-content/plugins/super-forms/uploads/php/files/9dde8a1f4a34131b2e039842671381fb/38681032374.pdf
    • https://wkd-uk.com/wp-content/plugins/super-forms/uploads/php/files/08b25172328dbfde9547ff850ab03c0f/75200199453.pdf
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160808f4e429a0---todevoxew.pdf
    • http://asbufestival.com/uploads/FCK_files/file/zuliweremizo.pdf
    • http://baovephuongtroi.com/vietkiendo/upload/file/wuvepudajiru.pdf
    • https://amerismithenterprises.com/wp-content/plugins/super-forms/uploads/php/files/fea0f7b719e61bd13165f32d60726378/lekotazupuval.pdf
    • https://nowackleverkusen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608610a2b57f7---75781316705.pdf
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/c1c9f91b5f538b16d77647c537604ed8/11563736469.pdf
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/16080e5c2b6433---gitebaniv.pdf
    • http://www.amedna.com/userfiles/files/23334769364.pdf
    • http://ned.ru/uploads/files/wuwuluvupuwepunot.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=is+it+better+to+sleep+late+or+wake+up+early
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f1d1.bin
99667750d3111a8f880074517ea82369f772baf1946a552b927cacb5099ef30e
pdf-font-stream PDF embedded font (sfnt) at offset 0xF1D1 10624 bytes
font_01_sfnt_off00010a25.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10A25 16792 bytes
font_02_sfnt_off00012237.bin
908e2ee720c17e1679de02131b0f98742826d6ded077b8d05489cf7d1273590c
pdf-font-stream PDF embedded font (sfnt) at offset 0x12237 17212 bytes