Malicious PDF — malware analysis report

Static analysis result for SHA-256 3fb837abe76f8ab3…

MALICIOUS

PDF

76.8 KB Created: 2021-04-06 04:50:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-02
MD5: 88851da0a729b9e2a78fdc7e9787d0e1 SHA-1: 527dd230a6ec21c71f05c8be90bef8d0e029aa45 SHA-256: 3fb837abe76f8ab3b643b15066f37fdafcca245a22d38f59d6dafca2cc338daa
186 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, containing numerous external links to other PDF files hosted on various domains, some of which are disposable. This technique is often used for SEO manipulation or to distribute further malicious content. The primary URL observed is https://kuzutuzo.ru/wix?keyword=vocab+level+c+unit+11+antonyms+answers.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://kuzutuzo.ru/wix?keyword=vocab+level+c+unit+11+antonyms+answers PDF link annotation
    • http://sokadap.22web.org/meri_pyari_behaniya_banegi_dulhaniya_song.pdfIn PDF document text
    • https://cdn.sqhk.co/zovitamojim/jeo89jh/torolufitop.pdfIn PDF document text
    • https://cdn.sqhk.co/wepugozotap/cqhe0Ar/zijalerupevodixumi.pdfIn PDF document text
    • https://cdn.sqhk.co/reparepoki/jcJjejg/usher_songs_2017_list.pdfIn PDF document text
    • https://cdn.sqhk.co/monazaxumol/figchJE/cowboy_good_morning_picture_download.pdfIn PDF document text
    • https://cdn.sqhk.co/kokuxisa/jj82Dhf/football_games_2017_nfl_2020.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://3d7304b5-8527-495f-b913-615d6f357a43.filesusr.com/ugd/ef7486_55b3e32603324ca7898995cc2b8d107f.pdf?index=trueIn PDF document text
    • https://cb70cc59-2297-49c3-b7e2-2ac7e26e28d4.filesusr.com/ugd/4479ed_ff3f2a3111024667a56e560e8c24bece.pdf?index=trueIn PDF document text
    • http://mafovipuvawo.epizy.com/56570181510.pdfIn PDF document text
    • http://jovebaben.epizy.com/movies_hd_bollywood_2017.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e310f151-2928-4de5-a552-9052ce5126e0/katifuz.pdfIn PDF document text
    • http://tuvivitir.rf.gd/signs_and_symptoms_of_peptic_ulcer_disease.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/250d568a-66cd-4f5d-8e3a-d91d97a0f6a0/how_do_i_use_my_lowrance_elite_7_ti.pdfIn PDF document text
    • https://7f793f8f-877f-420e-851b-8bae9ea62a4d.filesusr.com/ugd/78c764_e1c8bc2990884f9fb647690feceae5f6.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/9c625517-34f9-4abb-be24-0a83ce7c4a1f/shure_ulx_d6w.pdfIn PDF document text
    • https://01d67eed-50ba-4ccb-8f82-c1581f7ed07e.filesusr.com/ugd/e3325f_58ce130838e84786ba3798b13f04176f.pdf?index=trueIn PDF document text
    • https://c01188fd-d8af-4b86-846b-090f7ecd58d8.filesusr.com/ugd/9058e5_2db75b66609d4418ac33715ca4a09962.pdf?index=trueIn PDF document text
    • https://a9f3490c-def6-45ea-9957-aefa341d54bd.filesusr.com/ugd/84b587_62e44efd66eb4916b1c115af5b796795.pdf?index=trueIn PDF document text
    • http://murorutikuba.rf.gd/urbanismo_ecologico_mostafavi.pdfIn PDF document text
    • https://69b12d55-863e-458e-a545-ad358ed6bd1a.filesusr.com/ugd/a9642c_a758becc3a104337ad44ff8e10c236f0.pdf?index=trueIn PDF document text
    • https://307a23dc-bb60-4906-9a68-69e45957aa19.filesusr.com/ugd/d2057d_32783c5213d64b55834e0a79aedee3a1.pdf?index=trueIn PDF document text
    • https://36fde204-cda4-4268-899b-58717f9005d0.filesusr.com/ugd/b13063_8204d79ea6ea48cf874aa714932155ec.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_off0000f0f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0F0 5356 bytes
SHA-256: ac0e6e7c40f309132ad66648d1457a6f6db7395f42f48794f3305a722197ae8e
font_01_sfnt_off00010334.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10334 10184 bytes
SHA-256: d51a00608d2967d4c757507ee4dc80eb12bc33d469b59e5838a762d2f193e80e