Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f87f463a825581b…

MALICIOUS

PDF

79.0 KB Created: 2021-03-17 03:54:40 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: a971801f169bc17e8bc5b1268b03d909 SHA-1: ce156a66f45399fdc4b689a7dd99133dfcc2a74e SHA-256: 9f87f463a825581b08f6e2b518b39b7bbe4a5fee37b2dd44d43f8129b4b42755
216 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which are part of a link farm designed to improve SEO, but one critical heuristic identified a brand-impersonation credential phishing lure. The presence of multiple external URIs and a high ML classifier score further support this assessment. The document's content, though heavily obfuscated, appears to be a lure related to mathematical definitions, likely a pretext for the phishing attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9967

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
  • 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.
  • Brand-impersonation credential phishing lure critical SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: action link to abused redirector https://topigofifudonif.weebly.com/uploads/1/3/5/3/135304546/82939f321e2c.pdf.
  • 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://xezojetit.ru/123?utm_term=slope+intercept+form+of+a+line+definition PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4383916/normal_5fd7b24c12df7.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4414495/normal_5fe4f061cef12.pdfIn PDF document text
    • https://topigofifudonif.weebly.com/uploads/1/3/5/3/135304546/82939f321e2c.pdfIn PDF document text
    • https://tuwuribo.weebly.com/uploads/1/3/6/0/136027226/bakeworerivus_pakudefatududa_bewit_sejir.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4409393/normal_604a87492545a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486763/normal_6020428196116.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417528/normal_601e65447efeb.pdfIn PDF document text
    • https://duzigolanulemo.weebly.com/uploads/1/3/2/6/132680867/jigojanakokag_weronebepimo.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4498366/normal_5ffd476659fa9.pdfIn PDF document text
    • https://wobereresexo.weebly.com/uploads/1/3/1/6/131606335/2851273.pdfIn PDF document text
    • https://ritibamubube.weebly.com/uploads/1/3/1/4/131437410/muwikunavareni-ginesujidorex-zujesobazag.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454813/normal_6022c1f415f07.pdfIn PDF document text
    • https://nobuzuza.weebly.com/uploads/1/3/4/7/134757083/fosutemisovuka.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4494677/normal_5feebd16658fa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4473064/normal_60021f9901a18.pdfIn PDF document text
    • https://vutavevivusupe.weebly.com/uploads/1/3/0/7/130776898/6691285.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4444850/normal_6008af3dda6af.pdfIn PDF document text
    • https://jafedemigizol.weebly.com/uploads/1/3/4/5/134588438/dafanetadop-poxutikozi-fokepafi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/latufenaw/vakuwebaromamewomaju.pdfIn PDF document text
    • https://s3.amazonaws.com/fapaga/vomudufivobufonutugo.pdfIn PDF document text
    • https://s3.amazonaws.com/vokeri/replacement_for_western_digital_media_player.pdfIn PDF document text
    • https://s3.amazonaws.com/zarelusipofox/paverubegabo.pdfIn PDF document text
    • https://s3.amazonaws.com/loranoduzuja/google_sheet_templates_timesheet.pdfIn PDF document text
    • https://s3.amazonaws.com/sigobija/bonds_vs_stocks_historical_performance.pdfIn PDF document text
    • https://s3.amazonaws.com/bomifabipi/elementary_spelling_words_worksheets.pdfIn PDF document text
    • https://s3.amazonaws.com/wixatax/student_information_form_in_html_code.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_off0000f89a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF89A 5228 bytes
SHA-256: 67f7b51ba8b9e82a2fe28b6e0ef4efd2bf88b436753b6c64d47437bb9109209e
font_01_sfnt_off00010a4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A4D 10492 bytes
SHA-256: cd6193a05405383c55f4abff977e5633ed6ef4d9026a1353bbddbbf6659a2899