Malicious PDF — malware analysis report

Static analysis result for SHA-256 db7861470361d0c3…

MALICIOUS

PDF

91.2 KB Created: 2021-05-18 18:09:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 5214af64bbadecf0113c225460f586ba SHA-1: cf7869d66cd4e04811c764f64027c9542f3122cc SHA-256: db7861470361d0c3f890c9b2d2e96e1d54e1437899ddbd9569c3e1fbe68a3b33
126 Risk Score

Malware Insights

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

This PDF document contains a large number of external links, many of which point to disposable hosting and are likely part of a link farm designed to improve search engine rankings or redirect users. One prominent URL, 'https://mezovuduw.ru/strik?utm_term=how+do+i+reset+my+samsung+fridge+filter', suggests a lure related to common technical queries. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent behind the link farm and redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://mezovuduw.ru/strik?utm_term=how+do+i+reset+my+samsung+fridge+filter PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4391915/normal_5fe2523ee50b4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4497082/normal_5fd9670c8042b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4467915/normal_5fd13affef892.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4425511/normal_60663f913612b.pdfIn PDF document text
    • https://kaxesudinebeg.weebly.com/uploads/1/3/1/3/131379803/bifakeviseke_rukilawori_datagu.pdfIn PDF document text
    • https://xabizukilitexe.weebly.com/uploads/1/3/4/3/134335342/dokilivovajus.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4420745/normal_6016355d24fc8.pdfIn PDF document text
    • https://nadaroxiwe.weebly.com/uploads/1/3/4/6/134688146/gupepolutipewi.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4374009/normal_5ff8b3bdb1c02.pdfIn PDF document text
    • https://totuseki.weebly.com/uploads/1/3/5/3/135322554/seleluzi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://uploads.strikinglycdn.com/files/bb6683ce-9ad3-44c2-a22b-91e33bce82c6/xigekidetodozelivalejowu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a66a2253-05ce-49c7-817a-ad339b678b85/peter_drucker_books_online.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ecc0ed46-4ea6-40c2-91fb-bfc665c0c2b5/harman_advance_pellet_stove_parts.pdfIn PDF document text
    • https://s3.amazonaws.com/nowokil/ganpati_3d_photo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0ad3ac28-922b-4e9d-afb8-39415447dd54/microbiology_and_molecular_biology_reviews_submit.pdfIn PDF document text
    • https://s3.amazonaws.com/jixeremipet/malwarebytes_for_windows_7_free_trial.pdfIn PDF document text
    • https://s3.amazonaws.com/viromibukoleliw/how_to_build_biceps_and_chest_at_home.pdfIn PDF document text
    • https://s3.amazonaws.com/lopadivupudexa/10709511035.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fe0e278e-d819-4d7c-9e3d-c41b64ff3b63/75845696278.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010a2b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A2B 2968 bytes
SHA-256: 9d09da5f8339faf03d76552ffd4679db9a9978d7ca95b21340e42d8237d91475
font_01_sfnt_off000114d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114D2 5264 bytes
SHA-256: 4b11282f25edb80d5421cdf0b5eb96074442e5a33e39cf1221446f088913bb1e
font_02_sfnt_off000126b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126B7 12080 bytes
SHA-256: 3320e089fe4fb8c22ca1a86c2b210e2646465bff1b8f0a50cf4c4db8bbdac311
font_03_sfnt_off00014f57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14F57 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176