Malicious PDF — malware analysis report

Static analysis result for SHA-256 81edffd865e956d4…

MALICIOUS

PDF

89.7 KB Created: 2021-09-23 18:35:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 2e652b027076cf24eff72630c39281a0 SHA-1: a72efb80685210a0539cec7dd051dd6b64f722fb SHA-256: 81edffd865e956d469eefd07d7761b81ef63e55316ff48425696d65d8e129154
196 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and exhibits multiple heuristics indicating malicious intent, including PDF link farms pointing to compromised CMS uploads and disposable hosting. The presence of numerous external URLs suggests a phishing or malware distribution campaign, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9765

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://infrive.ru/uplcv?utm_term=adjectives+starting+with+letter+l+to+describe+a+person+positively PDF link annotation
    • http://mos-craciun-inchiriere.ro/fckfiles/file/28456131994.pdfIn PDF document text
    • https://silverbirdmarketing.com/pages/images/file/63493658695.pdfIn PDF document text
    • http://yanartextil.com/firma/files/17507466440.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16133b461624cd---janimotopelosepigab.pdfIn PDF document text
    • https://xcheck.vn/uploads/userfiles/file/41260157283.pdfIn PDF document text
    • http://qianxish.com/ckfind_image/files/10526577271.pdfIn PDF document text
    • https://delphin-restaurant.com/ckfinder/upload/files/ruxux.pdfIn PDF document text
    • http://aexpress.lv/index/images/up/file/kojebuvuwuru.pdfIn PDF document text
    • http://www.buildonhope.org/file/patotukolekedup.pdfIn PDF document text
    • http://cabinet-blin.fr/ressource/site-image/files/52034115421.pdfIn PDF document text
    • http://tercovci.cz/files/file/pemukuvopu.pdfIn PDF document text
    • http://www.fred-robin.com/ckfinder/userfiles/files/12171039178.pdfIn PDF document text
    • http://donateagift.eu/userfiles/file/vodugeler.pdfIn PDF document text
    • https://fitness-sport.it/userfiles/file/7932409256.pdfIn PDF document text
    • http://sbsinternationalschool.org/userfiles/file/16266747146.pdfIn PDF document text
    • https://daulte.ch/ckfinder/userfiles/files/rutavejot.pdfIn PDF document text
    • http://veterinarioassociatopacinidallatorre.eu/userfiles/files/89314373450.pdfIn PDF document text
    • http://hardiebase.com/uploads/assets/filefile/44562264019.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614a1195b64b1---43176605716.pdfIn PDF document text
    • http://studiomuraca.eu/userfiles/files/39137950196.pdfIn PDF document text
    • http://xn--80aafbladvtgxneccoge3bt.xn--p1ai/pict/file/ruzibu.pdfIn PDF document text
    • http://itcbeautytrainingschool.com/userfiles/file/puxusitipu.pdfIn PDF document text
    • http://lunaleo.pl/userfiles/file/29547820688.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16134ca9d2f3c2---wobivarowu.pdfIn PDF document text
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614be1b20d0d3---62260519002.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16137f26aad000---jirado.pdfIn PDF document text
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ea01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA01 1888 bytes
SHA-256: 228445a3744f13af4bf84041e55802a923554d86926eb0745489ea117e4ab105
font_01_sfnt_off0000f2ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2CA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010ae1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AE1 11312 bytes
SHA-256: 52c60f20bb9b77c804192e563583abd679d3dc1b2721f684e8b85207c9368fa1
font_03_sfnt_off000124fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124FB 19944 bytes
SHA-256: b6b6b1ad95b06c11ea88ee95f9eab2271b09c0273ae2c9d8fe3f5c7c94c9449d

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