Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b2bd2812167f5d…

MALICIOUS

PDF

92.1 KB Created: 2021-02-26 15:47:02 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 54cc029068a5534a05fd4069930e9043 SHA-1: a852ee12ddd1b04cb7924acd38548f4402fb06a1 SHA-256: 81b2bd2812167f5d5dd3dd5e4d1dace7fa460d9d794c9513ad547a6b7bec89b8
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links to external PDFs hosted on disposable domains, a common tactic for SEO manipulation or distributing malicious content. One critical heuristic identified a link to known malicious redirector infrastructure. ClamAV also detected this file as Pdf.Phishing.Trojan, further indicating malicious intent. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, but no direct instructions or executable scripts were found.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/wix?keyword=science+olympiad+ornithology+rules In PDF document text
    • https://liloxowilobo.weebly.com/uploads/1/3/4/2/134265539/renufanalute-suboramosibipa-gerazipagowod.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366630/normal_5fc6b194bcfe5.pdfIn PDF document text
    • https://naratejog.weebly.com/uploads/1/3/2/6/132682615/xumotim-baresomiku.pdfIn PDF document text
    • https://cdn.sqhk.co/janawezexoj/ZhitYgi/wellness_coach_jobs_near_me.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446045/normal_5fdb2de679d05.pdfIn PDF document text
    • https://tulapubilogu.weebly.com/uploads/1/3/4/8/134881906/8275034.pdfIn PDF document text
    • https://motixovelubebov.weebly.com/uploads/1/3/6/0/136085904/6564029.pdfIn PDF document text
    • https://kutemipemowu.weebly.com/uploads/1/3/4/8/134860595/b6e9a6b92102b4.pdfIn PDF document text
    • https://jurisosisirebak.weebly.com/uploads/1/3/6/0/136086550/womuzutavade.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415068/normal_6023ea0f64ab6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4426957/normal_5fc878fe1dd64.pdfIn PDF document text
    • https://jojeditisiteso.weebly.com/uploads/1/3/1/6/131606373/f9eabf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4426960/normal_6031cd37e6ebf.pdfIn PDF document text
    • https://tatazopizen.weebly.com/uploads/1/3/1/1/131163492/lewuvos.pdfIn PDF document text
    • https://jovigazever.weebly.com/uploads/1/3/1/6/131637362/tapukitavovirol.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4502493/normal_600a43953f634.pdfIn PDF document text
    • https://betijefozivur.weebly.com/uploads/1/3/0/7/130776077/gologabeloloxo-siberevid-tizonudax.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/galinikagopit/beamer_template_title_page.pdfIn PDF document text
    • https://s3.amazonaws.com/kibavutibeved/makepasewunej.pdfIn PDF document text
    • https://s3.amazonaws.com/dupula/baahubali_the_beginning_tamil_songs.pdfIn PDF document text
    • https://s3.amazonaws.com/bisute/graphic_novel_ielts_answers.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012c53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C53 5692 bytes
SHA-256: 4fa66efb0c8ff5e90284c257e0a990080e2371b913d8991a7f9f73e4d0d4b417
font_01_sfnt_off00013f8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F8D 10268 bytes
SHA-256: d639fc1003015257dca53c5964c6fb4cf115c7f65d041d18f38b202aa94aa195