Malicious PDF — malware analysis report

Static analysis result for SHA-256 636a4038ffe58475…

MALICIOUS

PDF

81.2 KB Created: 2021-10-04 20:04:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: d4f35ac466b0a4af05df380065d6763d SHA-1: 907298cbfe6e82bc00620bcfb9423c74a789ccc8 SHA-256: 636a4038ffe5847576febcb11e0150ee520e66620d49869cf4e4ca9f0595cbec
156 Risk Score

Malware Insights

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

The PDF was identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm. Several URLs point to compromised CMS upload directories or disposable hosting, suggesting a phishing or malware distribution scheme. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically highlights the non-clustered link farm nature of the document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 http://nj-rshb.com/v15/Upload/file/2021929137431680.pdf In PDF document text
    • http://bukharaatlanta.com/sites/default/files/file/98687921882.pdfIn PDF document text
    • https://guruvinodji.com/Userfiles/file/nusomifudo.pdfIn PDF document text
    • https://bloomlight.pl/_bloom/file/83574155967.pdfIn PDF document text
    • http://www.americaninvest.net/upls/files/xijenuz.pdfIn PDF document text
    • https://sassanoproperties.com/FCKeditor/file/mexawateb.pdfIn PDF document text
    • https://thisissati.com/userfiles/files/vavatexubagigedejuko.pdfIn PDF document text
    • http://otohondamientay.com/upload/files/mesimefozelajidamakefizi.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/161336d5e0640f---55915464816.pdfIn PDF document text
    • http://copy2d.com/ftp/image/file/71097447732.pdfIn PDF document text
    • https://projetounificado.com/uploads/files/1989992213.pdfIn PDF document text
    • https://cqhuaan.myhost360.cn/upload/files/10-01-19-51-19-80.pdfIn PDF document text
    • http://word.mn/uploads/assets/3879728512.pdfIn PDF document text
    • http://smeeing.com/userfiles/files/86212549738.pdfIn PDF document text
    • https://martan.es/cenavarra_userfiles/files/23886666440.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/ectkqaikap04u448uf8dgus2o4/40505012299.pdfIn PDF document text
    • http://zezoalza.com/ckupload/files/89425651955.pdfIn PDF document text
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/0acfe6f9e3cb67da97deff64eb76f71f/japupidulem.pdfIn PDF document text
    • http://stagegator.scorchmark.com/stagegator/ckfinder/userfiles/files/6533900966.pdfIn PDF document text
    • https://www.rogierstoel.nl/wp-content/plugins/super-forms/uploads/php/files/tv8l51g1dkqjuq69fjbp0cibvg/16340069711.pdfIn PDF document text
    • https://accidentmatters.com/ckfinder/userfiles/files/12899723723.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=spanish+moss+and+treesPDF 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_off0000d5b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5B5 19252 bytes
SHA-256: 519102782f2bda7e1fc826623d8dec12af07cfeb40afecc1e71285ab16c4ae90
font_01_sfnt_off00010754.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10754 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F6B 10684 bytes
SHA-256: 08de7dc14ed653cea23ab1398c0974a7ea1728c7ba2e271e1033fba6b22306e9