Malicious PDF — malware analysis report

Static analysis result for SHA-256 53924f55209340e7…

MALICIOUS

PDF

78.4 KB Created: 2021-05-29 09:31:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: cf3755fca3063c5fb32bc2a2e9a3b10e SHA-1: 21196edcb10cf67c95e0aca4a09e4d7a2b5e9b94 SHA-256: 53924f55209340e73fd00aa575a14801e7527c24d88270d256e8974a5a45f267
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file contains a large number of external links, many pointing to disposable domains, indicating a link farm or SEO spam operation. The presence of 'wkhtmltopdf' in the metadata and the ML classifier's high confidence score suggest malicious intent. While no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of malicious document delivery, likely as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://vilenefex.ru/123?utm_term=lightweight+sheetrock+mud+home+depot PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4493905/normal_5fd1149aae3d6.pdfIn PDF document text
    • https://zixotojene.weebly.com/uploads/1/3/4/3/134315054/mefolijik-narifamivepopo-karuwizuv-pavebexuwe.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4451565/normal_5fc8474d297a2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4473031/normal_5ff666b904950.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4422643/normal_6003e60944b3e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489595/normal_5fe8508d556b3.pdfIn PDF document text
    • https://fajuvupo.weebly.com/uploads/1/3/5/3/135310445/ribenikexo-gomonezopupopor-wigosago-waxuf.pdfIn PDF document text
    • https://sulogaxelope.weebly.com/uploads/1/3/1/4/131438888/08f649f.pdfIn PDF document text
    • https://nizotuzuwiza.weebly.com/uploads/1/3/7/5/137507555/6643675.pdfIn PDF document text
    • https://wuzesitawe.weebly.com/uploads/1/3/4/7/134733123/7270522.pdfIn PDF document text
    • https://kolivobaka.weebly.com/uploads/1/3/4/5/134500933/5161516.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481273/normal_60668b659bc73.pdfIn PDF document text
    • https://xakelagus.weebly.com/uploads/1/3/3/9/133997825/kowiruwej.pdfIn PDF document text
    • https://kimonasisu.weebly.com/uploads/1/3/5/4/135400987/vofekixi.pdfIn PDF document text
    • https://pudajokorafub.weebly.com/uploads/1/3/7/5/137516447/bavakewegasam.pdfIn PDF document text
    • https://semufukat.weebly.com/uploads/1/3/1/8/131857602/8405274.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413004/normal_603685fc76f84.pdfIn PDF document text
    • https://tabodixab.weebly.com/uploads/1/3/4/5/134585887/b81bb0abc9.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/6a5b7c8d-3873-4ad3-b37c-e21eba18761a/verizon_lg_4g_lte_tablet.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/38bf6312-5be9-482c-9f21-cd847102c296/sowutasuvaluvitegez.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/98c5d953-987b-4acd-9500-dd8c3916254e/lomibulerovow.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/714c98bf-f2d7-4b68-876f-5eae0650b2a5/tabewejereberedexekegajub.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/96973f7b-f30b-4356-9449-3ff4c3a49331/swisher_44_mower_belt_diagram.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f402.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF402 5344 bytes
SHA-256: 7c0cdedb608bdc9dd5aae39e9285ae412933a3e47b361c43496bda24152340f6
font_01_sfnt_off00010621.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10621 11360 bytes
SHA-256: 524f60e5d82de1add5febd0da9dc40adf578e0c9814d6df78926ce727cdd268b