Malicious PDF — malware analysis report

Static analysis result for SHA-256 c755140717e9a035…

MALICIOUS

PDF

79.7 KB Created: 2021-04-29 20:02:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 91d072706b08c79e173084c5c2f9862b SHA-1: 9a88955fb80c02b3400f87bde480c7e018202823 SHA-256: c755140717e9a03584b7d5676449b4b313ac64fbfe60bf1bd8eab9648e9e7bc3
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO manipulation tactic. One of the embedded URLs, https://jacksth.ru/strik?utm_term=who+do+you+call+to+fix+a+dishwasher, is particularly suspicious due to its structure and the UTM parameters. The ML classifier also strongly flagged this PDF as malicious, supporting the assessment of a malicious link distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 5

  • 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://jacksth.ru/strik?utm_term=who+do+you+call+to+fix+a+dishwasher PDF link annotation
    • https://zepukuliro.weebly.com/uploads/1/3/5/9/135964459/sujimas.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451750/normal_601548711de3c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413848/normal_5fd8fd165d107.pdfIn PDF document text
    • https://dasewukux.weebly.com/uploads/1/3/5/9/135956745/63ca871c61add35.pdfIn PDF document text
    • http://dutarotanazosuv.medianewsonline.com/moxil.pdfIn PDF document text
    • http://ideal-it.fun/nlt_study_bible_red_letter_hardcover_cloth_bluel32n5.pdfIn PDF document text
    • http://busforpay.online/lasemugunegukisl52q4.pdfIn PDF document text
    • https://rixabala.weebly.com/uploads/1/3/4/7/134730828/rabusave.pdfIn PDF document text
    • https://vilawamilufulob.weebly.com/uploads/1/3/6/0/136006615/2964929.pdfIn PDF document text
    • http://mihetos.xyz/gisozavoraturogaluglufe1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4407991/normal_6017ddf062c15.pdfIn PDF document text
    • https://zoponexe.weebly.com/uploads/1/3/1/6/131606878/pexoxugowokadi.pdfIn PDF document text
    • https://lagipadule.weebly.com/uploads/1/3/5/3/135301279/9258338.pdfIn PDF document text
    • https://gixinizolovuz.weebly.com/uploads/1/3/5/3/135348456/3536763.pdfIn PDF document text
    • http://naturwows.space/pinball_game_windows_for_pc90u5l.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385021/normal_601ec0456032d.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://30de3caf-c510-4ce9-8691-b8280dc60d9b.filesusr.com/ugd/4980ee_c5f5b78bea9941ad8ecbe0f77368ac77.pdf?index=trueIn PDF document text
    • http://rurebafib.onlinewebshop.net/nutritional_anthropology.pdfIn PDF document text
    • https://69df74eb-9f83-488d-97bb-abb55063df61.filesusr.com/ugd/f34323_145550fc2c5f439e9c4dc33664c41746.pdf?index=trueIn PDF document text
    • http://wejufutaz.onlinewebshop.net/calendar_2020_june.pdfIn PDF document text
    • https://18cceff7-6d50-42ec-9d85-67184b61345e.filesusr.com/ugd/8c2e83_2660246cea474ecdb235d95dbb1ee487.pdf?index=trueIn PDF document text
    • https://69a21580-3c80-4f81-8097-1ec0bc18215d.filesusr.com/ugd/bd7df1_e781fbd6b6a048059b58a8230940cc83.pdf?index=trueIn PDF document text
    • https://c09438b0-f1cf-4ade-afa2-d322e048c450.filesusr.com/ugd/313cc6_f92d7d76ea7242fbb97170025651b0b4.pdf?index=trueIn 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_off0000f88c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF88C 5384 bytes
SHA-256: 5ec6ec29f5a3edf729c39565bdd534c9253f672807de80c4e9d15ebf83b29bac
font_01_sfnt_off00010afc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AFC 10884 bytes
SHA-256: f426364c90c7cd7b99aa32300b14944518f3a342ae182bf12cb71077336ff734