Malicious PDF — malware analysis report

Static analysis result for SHA-256 b104dbdf7ddbfa77…

MALICIOUS

PDF

76.0 KB Created: 2021-04-07 20:22:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-10
MD5: 2c134ece8f283870ab105064615d82cd SHA-1: 071eea3211ed794af284bd58bdd170b8df37f638 SHA-256: b104dbdf7ddbfa779e8c60ce28ea334fcf84c0079f2c1828f32d91fdc4d3bd42
186 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains a significant number of external links, with many pointing to disposable hosting, indicating a potential link farm or phishing attempt. One critical heuristic specifically flags it as a 'PDF_SEO_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM'. While no scripts were explicitly extracted, the presence of external links suggests an attempt to redirect the user to malicious content, possibly via embedded JavaScript, which is common in malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • 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=interior+designing+in+karachi+university PDF link annotation
    • http://nosinoski.shop/sofewumezagadelipijugs08g.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368745/normal_603c04cfc3933.pdfIn PDF document text
    • http://allieshouseofhope.com/58172799078t6q58.pdfIn PDF document text
    • http://naturaitalia.space/5640781401wpy75.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4452389/normal_5fc90d6c443b6.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/d2473e1d-28ee-4c89-a2f6-8488be55bb08/the_7_sorrows_of_mary.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/bfc97b39-51f3-45cd-bb1a-664283e57b6b/learn_how_to_do_division_problems.pdfIn PDF document text
    • https://s3.amazonaws.com/wutezigojuxi/hongkong_land_holdings_limited_annual_report_2017.pdfIn PDF document text
    • https://51fd5013-30c4-43d1-89ce-86564632a3b5.filesusr.com/ugd/9f06f8_39d39a9be54646218eff1e55303b6954.pdf?index=trueIn PDF document text
    • https://85ed388a-52e0-4e79-9737-9d4b769dda71.filesusr.com/ugd/bb10c5_68d5cc6fa4d449deb66837086471416e.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/xetasif/kororikawid.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3979d61e-6bde-41c1-b309-6173a1a1f584/the_vampire_diaries_the_awakening_audiobook_online_free.pdfIn PDF document text
    • https://fefcf4f0-bf52-4086-adb3-b788df03f7bd.filesusr.com/ugd/da9d4c_2b50c881007c4ce19c3c1acf985fdd98.pdf?index=trueIn PDF document text
    • http://namepafubi.atwebpages.com/characteristics_of_democratic_leadership_style.pdfIn PDF document text
    • https://s3.amazonaws.com/batiku/fire_go_bun_dem.pdfIn PDF document text
    • http://sanugifop.atwebpages.com/what_holidays_is_the_federal_reserve_closed.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5673b778-26bf-4b31-9158-f4a717429526/33944498175.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0d1ff7da-1c9d-4a16-be50-09bf5cfd9388/lg_tromm_washer_le_error_code.pdfIn PDF document text
    • https://75e6061f-eb7a-4ce8-b546-077bf96366c3.filesusr.com/ugd/2dfd19_6cdc7b6f569149e78973196e7e9d837d.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_off0000ea9f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA9F 5332 bytes
SHA-256: a7855d2cf9f62cba5581cf291191010b99d925d772fc2ff09b427450d50c83cf
font_01_sfnt_off0000fcc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCC8 10712 bytes
SHA-256: 9e0ee0485459e9fe7ba85356a8fbe78590f576d27f9cd50f418ec81a5c29642e