Malicious PDF — malware analysis report

Static analysis result for SHA-256 996a6f739c0c64e1…

MALICIOUS

PDF

80.1 KB Created: 2021-03-16 14:26:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 81bfae736c7f719d4e96f7b69a167b78 SHA-1: a72324417fd87c90107c85cea34adee4acedcc51 SHA-256: 996a6f739c0c64e106f6ef2265cba39e138a077ecdbb889d4a404f9d5ae2147d
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file is identified as malicious by multiple heuristics and an ML classifier, indicating a phishing or trojan-like behavior. It functions as a link farm, directing users to various external PDF files hosted on disposable domains, likely to distribute further malware or engage in phishing. The primary lure appears to be offering free downloads of academic materials.

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://resalured.ru/award?keyword=brunner+and+suddarth+14th+edition+pdf+free+download PDF link annotation
    • http://zaxevef.getenjoyment.net/81264952472.pdfIn PDF document text
    • http://mojofaza.mypressonline.com/2738028993.pdfIn PDF document text
    • http://davebamonuzove.medianewsonline.com/59066947053.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/717e4d29-afa3-474c-b912-d33a9a4f55fd/9974539536.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/14ea9172-6d8a-427e-a401-da29e1ed5af1/throne_of_glass_book_1_free_read.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fdf604ce-8121-41ae-a089-abb093c3b450/stanley_battery_charger_flo_dead_battery.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d9d7790c-4922-4322-bec2-89f2974e8e8b/letanotimowozafudarid.pdfIn PDF document text
    • https://4be8a7ba-6c9a-47a4-99fc-a5961b41a404.filesusr.com/ugd/132250_e6b52d02a4644153a5f245bb7965dd16.pdf?index=trueIn PDF document text
    • https://ecab545c-19d2-4654-b6ac-fb8b9749f5ba.filesusr.com/ugd/e5412a_60d2c3402e474344b7634b327d56a24d.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/d0df7fae-4722-4f2a-bb19-9bd9298c9f04/ejemplos_de_citas_con_formato_apa.pdfIn PDF document text
    • http://donijexufenu.onlinewebshop.net/6213879773.pdfIn PDF document text
    • https://6762652a-e869-40f3-960d-1446d4066230.filesusr.com/ugd/55e6b1_8fef32e298514a3ba4101e5d3a90c895.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/gonafoziguwewe/after_book_4_summary.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/10c1a80b-2607-4ff4-be8f-3c3fad6f4e4f/39317911779.pdfIn PDF document text
    • https://s3.amazonaws.com/sagotomagin/zifuwitemamusabewola.pdfIn PDF document text
    • http://sujawokasafu.onlinewebshop.net/ccna_security_exam_cost.pdfIn PDF document text
    • https://s3.amazonaws.com/xurixado/link_s_awakening_eagle_tower_guide.pdfIn PDF document text
    • https://s3.amazonaws.com/farowug/vampire_diaries_book_14.pdfIn PDF document text
    • http://xipanizi.myartsonline.com/bifilalomidutoxejepuwo.pdfIn PDF document text
    • http://levapoloj.onlinewebshop.net/lenix.pdfIn PDF document text
    • https://s3.amazonaws.com/vukumesoj/xiwoninajizix.pdfIn PDF document text
    • http://pisonepegosa.myartsonline.com/17848920192.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a3bbc5a8-55ac-446b-9733-8cf97b38d93f/99578813855.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1b4acb4d-252f-4a08-a4d0-0cc1a356e2d0/remington_700_sps_ss_30-06_stainless_steel.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/020c64f8-0c76-4bdc-8e2d-2f6ab7c9b31c/how_truly_radical_was_radical_reconstruction.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_off0000fa08.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA08 5408 bytes
SHA-256: f0d7f3b1da47a91d35c3b6a3cea56a8ad3fa55b87c205b79d2e5f9a9c1a395ef
font_01_sfnt_off00010c88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C88 11196 bytes
SHA-256: db2f0c04250ad39f5e42e4d14360d96aa03f79ec403bfda7f620c7b37b5c7835