Malicious PDF — malware analysis report

Static analysis result for SHA-256 74391e697e497106…

MALICIOUS

PDF

87.2 KB Created: 2021-03-25 02:07:11 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 6c3575e213314b8f294f7eb2624f2f17 SHA-1: 52170a07dcc7f2ea4cb5ec8b904f961e775dfd2c SHA-256: 74391e697e4971062f77692e515373d4dbfcfb9942f80ce3c6e90dfa8a7f3408
186 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many hosted on disposable domains, characteristic of a link farm used to distribute malicious content or conduct phishing. The primary external URL, https://pelibifir.ru/wix?keyword=internal+frog+anatomy+answer+sheet, suggests a lure related to educational content, likely to trick users into clicking through to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://pelibifir.ru/wix?keyword=internal+frog+anatomy+answer+sheet PDF link annotation
    • https://nesujuge.weebly.com/uploads/1/3/1/4/131407687/6475043.pdfIn PDF document text
    • http://vinograd.io/87352778409euvkl.pdfIn PDF document text
    • https://lurenosofen.weebly.com/uploads/1/3/0/7/130740325/sipuri.pdfIn PDF document text
    • https://tiwebusimevadeb.weebly.com/uploads/1/3/5/3/135346158/5686705.pdfIn PDF document text
    • http://dajexori.mypressonline.com/changing_dewalt_735_planer_blades.pdfIn PDF document text
    • https://jimuvidagonolab.weebly.com/uploads/1/3/1/6/131636746/4122918.pdfIn PDF document text
    • https://tusigidufamem.weebly.com/uploads/1/3/5/3/135350313/wavugup-dawuk-kefefavobajunix-tiwiwegekusobo.pdfIn PDF document text
    • https://gutasoleniv.weebly.com/uploads/1/3/4/4/134481560/e9ca39d6.pdfIn PDF document text
    • http://helpcenter.business/bufomiserinezajenabadqfosm.pdfIn PDF document text
    • https://pagilosotutan.weebly.com/uploads/1/3/0/9/130970008/4bb5eb49.pdfIn PDF document text
    • https://gagufivelorifig.weebly.com/uploads/1/3/4/5/134596616/fomob_rivadawavari_rinavetafetig.pdfIn PDF document text
    • https://ritosigom.weebly.com/uploads/1/3/1/4/131453630/mikijobaduze.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://bc5ba30c-e427-49eb-abc4-9677f18f04c1.filesusr.com/ugd/bcd086_16e71b8f97b640d995470770c3009978.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jiwotarotavuz/what_is_another_word_for_sunshine.pdfIn PDF document text
    • https://5b0e1d79-1acc-45ba-a965-31015372eee8.filesusr.com/ugd/67f5f7_a59d581984dc458a9649a538333ced16.pdf?index=trueIn PDF document text
    • http://vidugozu.atwebpages.com/77054577626.pdfIn PDF document text
    • https://s3.amazonaws.com/kegubinefuda/what_does_150_psi_mean_on_an_air_compressor.pdfIn PDF document text
    • https://s3.amazonaws.com/pisedij/inno_russo_armata_rossa.pdfIn PDF document text
    • https://s3.amazonaws.com/sitok/bticino_living_now.pdfIn PDF document text
    • http://vefodipox.myartsonline.com/study_bible_for_pc_free_download.pdfIn PDF document text
    • https://91953a53-6f32-4f2a-9b2e-0f954541ff31.filesusr.com/ugd/dad90e_45698bbac2d9457b8eecadb1e10f1628.pdf?index=trueIn PDF document text
    • https://45ed8376-e832-497f-ab20-0a31924dc5db.filesusr.com/ugd/4b7290_c7777daff7b24c24a221ec73d9ef96ef.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jepinebawo/c_programming_language_tutorial_youtube.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_off00011853.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11853 5312 bytes
SHA-256: 71562ab86fde0499b28568cdbd3de8bb1bab2760cf5750a5719fc33cc09eaffb
font_01_sfnt_off00012a53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A53 10740 bytes
SHA-256: af0ebed6f2525e5be8f48e826788319ed45ae4a714911062e0acfbafb2ce4846