Malicious PDF — malware analysis report

Static analysis result for SHA-256 27427c5e60f82d43…

MALICIOUS

PDF

84.4 KB Created: 2021-06-13 20:17:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-15
MD5: e2f29a1dddc0f9829b17a47c0cd1d582 SHA-1: 6651c10b0198afa68953d1daf1d38331c80dbc6a SHA-256: 27427c5e60f82d439725616307f32db75538bda56f7fcec5a5c16cf5fb240b8e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file that contains numerous external links, many of which point to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate maliciousness, specifically a phishing or trojan payload delivery. The document body is heavily obfuscated, preventing a clear understanding of its immediate purpose beyond directing users to external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://infrive.ru/uplcv?utm_term=water+activity+and+moisture+content+pdf PDF link annotation
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/4jcdlmaomt00r84m0imm3cjt4r/zepik.pdfIn PDF document text
    • https://www.ideaklinikbursa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607465692b31e---xupiwupejapojodotuboton.pdfIn PDF document text
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b1f1bb0d55c---tesawuwodoposozukofena.pdfIn PDF document text
    • http://dentherapia.hu/files/file/40152964013.pdfIn PDF document text
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/aa6eebd4efd20bc4d94b6534d0a79928/25189652122.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/f3626d9c872607b68e1c2473d7ef03b1/sumezoxowivaziluxusez.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/baxefepudafubipibulomed.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abb5953bcd7---66928782298.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/nahji4ed125257ofkc0vejv4jo/jarujikax.pdfIn PDF document text
    • https://gaseg.com/wp-content/plugins/super-forms/uploads/php/files/49ar8g319p6dl9lia33nspdtjs/8110819921.pdfIn PDF document text
    • https://matrainagycsalados.hu/userfiles/file/24908258817.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608eb39c8b4dd---42827812081.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160909cf051cf8---sufifujirasoxuxazisejodo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn 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_off0000f390.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF390 5444 bytes
SHA-256: 37596fd76733f49132ac60e1969e349e6cfaa9ac55de2269b391209b54588f4c
font_01_sfnt_off00010617.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10617 12204 bytes
SHA-256: fb62fc7b875f12a636f446946b7da110e3d6d34542282bb45bb114582b2141ae
font_02_sfnt_off00012f75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F75 16112 bytes
SHA-256: 04c641d0aedeaa8c494855f42a2e9ae6fad9e3679126e7dc5c08fccc4b41c292