Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a16c405869093fc…

MALICIOUS

PDF

89.0 KB Created: 2021-07-24 08:38:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 321e712c9f5bff5882a308da200bd91b SHA-1: 5b727c40ebd8ce6a43b23fc2e7e8174788d75556 SHA-256: 4a16c405869093fc381049a39879954e77f5705e7108562db94a231591c124e7
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to compromised WordPress upload storage and other disposable hosting sites. The embedded URLs suggest a phishing or malware distribution scheme, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://www.varisistanbul.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f5fcad5044---64972984868.pdf In PDF document text
    • https://cornwallstaffagency.com/userfiles/file/4082914192.pdfIn PDF document text
    • http://kxnjl.com/userfiles/files/27918577041.pdfIn PDF document text
    • http://amon-syotengai.com/userfiles/file/wexenopafewe.pdfIn PDF document text
    • http://tuanlongland.com/upload/files/famoxoxidamezites.pdfIn PDF document text
    • http://baiduvpn.com/upload/files/24403240658.pdfIn PDF document text
    • https://zzhqhi.com/d/files/27402816423.pdfIn PDF document text
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/6mun35r11q112ccl7g1jlr7u28/toreguwil.pdfIn PDF document text
    • https://clap-bas.com/userfiles/file/dawidomivo.pdfIn PDF document text
    • https://birsamundapark.in/userfiles/files/pegajutopuri.pdfIn PDF document text
    • http://orbitsecurity.qa/pro_mvp_tech/uploads/file/jezosomumunojizugazivavi.pdfIn PDF document text
    • https://ferdavagnar.is/images/fck/file/65562884078.pdfIn PDF document text
    • http://bigyikesmedia.com/home/xtremweb/public_html/consultinstitute/web/upload/files/42880407660.pdfIn PDF document text
    • http://principessavencanice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076584f0ae65---xalupavirodewab.pdfIn PDF document text
    • http://loaamtran.com/files/usersfiles/files/51257311667.pdfIn PDF document text
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/f505cec6933e82be277c3c89a43f5f02/newepuminolefazawovizat.pdfIn PDF document text
    • https://securitydm.com/slicice/file/8048948955.pdfIn PDF document text
    • https://www.web2business.pt/wp-content/plugins/formcraft/file-upload/server/content/files/1608366405ac43---83389908470.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab69df76691---47040445003.pdfIn PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c7a5fda389c---53156652432.pdfIn PDF document text
    • http://stacjaregeneracja.pl/userfiles/file/nodebadube.pdfIn PDF document text
    • https://inifd.london/uploads/file/12611153046.pdfIn PDF document text
    • http://ottotech.center/userfiles/file/xowobilotavapulixi.pdfIn PDF document text
    • http://www.serenissimaservizi.com//files/3909631942.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+calculate+compound+interest+on+home+loanPDF 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_off0000f7d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7D0 10956 bytes
SHA-256: 48e32ffafdef867451132cce28d89a7b07dc16ddd2fb7cad01e17d50b9c34d35
font_01_sfnt_off000110fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110FD 17248 bytes
SHA-256: e3a91e7f3fd0bd10aa373fb11314b7461678e5faec6c2bacc66b10cc851bf2ed
font_02_sfnt_off00013e69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E69 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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