Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5481bdc7cd25fb8…

MALICIOUS

PDF

80.5 KB Created: 2021-09-19 11:01:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: d2c6833ce5691d1cf3d9c85ce0752d3f SHA-1: e15bd68a21ea892cde9f79fc8ef5b78150df11de SHA-256: a5481bdc7cd25fb813b848b7d6426546e9ce0ee1a1e9f0c8d42c16edd9676c13
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. No scripts were extracted, but the structure and URL patterns are consistent with a malicious PDF used for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://krisoc.ru/uplcv?utm_term=android+app+always+on+display PDF link annotation
    • http://webbuilders.com/files/file/45248846753.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c9a19a775d---kenorepetoj.pdfIn PDF document text
    • http://nawoo.net/userData/board/file/rorejago.pdfIn PDF document text
    • http://isemya.by/modules/ariol/static/ariol/ckfinder/files/xojugeli.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/1612fb719691a2---sixulokugaposafuzosa.pdfIn PDF document text
    • https://billard-hauri.ch/userfiles/file/7215416397.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a06ba35d67---vawatafizowupinagegubo.pdfIn PDF document text
    • https://activepymes.com/pub/file/tipopefufotagozogibujas.pdfIn PDF document text
    • http://bdnchem.com/upload/files/dodorasasekejosotat.pdfIn PDF document text
    • http://srs-budapest.hu/uploads/files/55438959999.pdfIn PDF document text
    • http://skoleniridicubrno.cz/ckfinder/userfiles/files/bewipububuzi.pdfIn PDF document text
    • http://www.ih-consultant.com/ckfinder/userfiles/files/jeriwadefikokoxexafanivej.pdfIn PDF document text
    • https://windfreeklima.com/upload/ckfinder/files/ridajifopezedimewibawam.pdfIn PDF document text
    • http://antansconstructions.com/ckfinder/userfiles/files/23579993118.pdfIn PDF document text
    • https://marugame.hk/editor_upload/file/29654381267.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/7dbef6e7680a9df4e7cc534068133990/85365501919.pdfIn PDF document text
    • http://qishuochem.com/siicea/userfiles/file/20057776418.pdfIn PDF document text
    • https://cambodiadriverservice.com/userfiles/file/25904543554.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/vidiwazababapir.pdfIn PDF document text
    • https://htchninc.com/d/files/82513546693.pdfIn PDF document text
    • https://wasael.com/userfiles/file/jetekor.pdfIn PDF document text
    • https://ohcsi.com/ckfinder/userfiles/files/gisevaworoxuvekududuwive.pdfIn PDF document text
    • http://quimicahj.com/admin/userfiles/userfiles/file/25307701468.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d851.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD851 17188 bytes
SHA-256: 7a35d2c3f0e788ece6b28eb284de3c1c57f0307ccdee7d0e29659abc87140f46
font_01_sfnt_off000104d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104D8 10336 bytes
SHA-256: 77aa8605892e6bc9f8c090b01f48de5dfe7c060463a520ec7980b7f076920213
font_02_sfnt_off00011c45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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