Malicious PDF — malware analysis report

Static analysis result for SHA-256 82075e0514a31483…

MALICIOUS

PDF

90.7 KB Created: 2021-09-16 08:27:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 844df26c07ee465883d170152d80cb84 SHA-1: bb5794e5cfcbb8c68cecbcf4e41815d0aa7b076b SHA-256: 82075e0514a314836c480216d1968b517f7e319394792633d449f0b1fcd69957
116 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm pointing to multiple compromised websites and disposable hosting, indicating an attempt to redirect users to malicious content. The ML classifier strongly suggests maliciousness, and the malformed stream length heuristic indicates potential exploit activity. Although no scripts were directly extracted, the PDF structure and embedded URLs are indicative of a phishing or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://thietkewebsite.btccorp.vn/uploads/files/59533947946.pdf In PDF document text
    • http://csc0311.com/userfiles/file/20210914135457_i52krc.pdfIn PDF document text
    • http://morenoroofing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a83708a264---69747040185.pdfIn PDF document text
    • https://onlinendttraining.com/files/82030767055.pdfIn PDF document text
    • http://contelex.it/userfiles/files/28294971712.pdfIn PDF document text
    • http://kavtas.com/images_upload/files/26744218670.pdfIn PDF document text
    • http://yves-segers.be/userfiles/files/70387727584.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/16135050ec9de6---potupewod.pdfIn PDF document text
    • http://paddockj.com/user_data/editor/ckfinder/core/connector/php/upload/files/jejixidejeso.pdfIn PDF document text
    • https://needlugs.com/userfiles/files/kanaximokodusoxe.pdfIn PDF document text
    • http://woonhuislift.info/wp-content/plugins/formcraft/file-upload/server/content/files/16138fb8459e79---77337783641.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/161355ac68d519---miforebazasujosu.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/75822285843.pdfIn PDF document text
    • https://sitpchemcieszyn.pl/_sitpchem/file/levodaralepositimebuj.pdfIn PDF document text
    • http://beming.com/ressource/site-image/files/wopem.pdfIn PDF document text
    • https://emenu.hu/editor_up/96427108591.pdfIn PDF document text
    • http://nc-israel.ru/upload/files/88391471107.pdfIn PDF document text
    • http://gazdalkodjokosan.hu/img/userfiles/file/80612198343.pdfIn PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614223dc2c604---mowuzududigadur.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613219642d6db---tagavutu.pdfIn PDF document text
    • http://bronia.org/userfiles/file/20734389153.pdfIn PDF document text
    • https://faresaldabbous.com/uploads/files/pugamazafitilunuwadetek.pdfIn PDF document text
    • http://clair-environnement.eu/catalogue_dynamique/file/zisufufogarijuparirolim.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=pretty+words+starting+with+aPDF 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_off0000ff3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF3C 17580 bytes
SHA-256: 3ceda02bcbd80899d8d3a3c28c1a78f320ee5777994d44b3856e51e40dfacb15
font_01_sfnt_off00012c86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C86 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001449d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1449D 10684 bytes
SHA-256: fe8b93293da76077dcc6800629af8a914b273f37c1f8acbec787713e97a6c718

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