Malicious PDF — malware analysis report

Static analysis result for SHA-256 77b031d1e3a12b5a…

MALICIOUS

PDF

87.1 KB Created: 2021-03-04 16:24:42 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: a67648eee5160626b10791af0ad8adee SHA-1: 1a29d8a6ff461471f530cda3b90c10e8283e061b SHA-256: 77b031d1e3a12b5aac528d13a4bc37fe3fc954844653ceaf61749fc169849570
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm, as indicated by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The document body, though heavily obfuscated, contains text related to 'Learn korean language in 30 days pdf' and 'wkhtmltopdf', suggesting a lure to disguise the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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 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://soxebez.ru/123?utm_term=learn+korean+language+in+30+days+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4365562/normal_603960878f7c1.pdfIn PDF document text
    • https://cdn.sqhk.co/ladesajisama/dpgfiug/remove_unwanted_object_app_download.pdfIn PDF document text
    • http://eglo.club/shark_lift_away_steam_cleaner_not_workingonywq.pdfIn PDF document text
    • http://samyog.ru/sanyo_43_inch_4k_tv_reviewfwavo.pdfIn PDF document text
    • https://cdn.sqhk.co/xinoxoxojib/biijbKR/mod_map_portugal_euro_truck_simulator_2.pdfIn PDF document text
    • http://uscreditcheck.info/what_are_the_rules_for_fractionsqucun.pdfIn PDF document text
    • http://hytri.com/maze_runner_2_full_movie_downloadg5dfb.pdfIn PDF document text
    • http://magnitoli-2ekran.site/lazipewufuminemanolefuko73wqt.pdfIn PDF document text
    • http://rte-ita.fun/44693835558iak50.pdfIn PDF document text
    • http://medgaj.com/fun_home_alison_bechdel_barnes_and_noble89qxt.pdfIn PDF document text
    • http://mydenverneighborhoods.com/json_tutorial_javatpointggt6n.pdfIn PDF document text
    • http://new-leggins.site/60499832489oyjnm.pdfIn PDF document text
    • http://slmit.space/identify_types_of_pronouns_worksheet_with_answersh5deh.pdfIn PDF document text
    • http://fastpeysistem.online/bixejakimimuwigoq538.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4457849/normal_602b5f3da2f1f.pdfIn PDF document text
    • http://reduslimitaly-ufficiale.website/descargar_dj_virtual_7_gratis_en_esp2eac4.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://1ce8651a-bfbb-4b9a-b1bf-24b3b574775a.filesusr.com/ugd/ac72e0_e7678778d9af41a39b350790bd3919dc.pdf?index=trueIn PDF document text
    • https://73e25548-3913-4bbb-aa69-a1b25f69568d.filesusr.com/ugd/cece23_90b0221590f643f1850368fd8dcb439b.pdf?index=trueIn PDF document text
    • https://c5e26362-acc3-4c40-9db4-ce0cbd355080.filesusr.com/ugd/681527_0fb0fba6193e4e7cb8a3c83a6e4725af.pdf?index=trueIn PDF document text
    • https://1eb42bdc-3da6-4b32-b75f-4382f1721f8e.filesusr.com/ugd/35474d_fd6ec32b2f5d4c99a55a92ff5fc62c7c.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000103e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103E5 4848 bytes
SHA-256: 480cdcaf44c3ac7c951f4da0ef604ee14b68572fb1bd34162eb8ef63817a8dd1
font_01_sfnt_off000114d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114D7 5624 bytes
SHA-256: 294eed679eafb7e9502872f7c822f3c183677fc39bbc1023a603bd6d6ce83ce8
font_02_sfnt_off0001281d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1281D 11160 bytes
SHA-256: aff1c3ea0d76748eca62a21b008bc0a5530b0d1f689725686af95e4ace97eb03

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