Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4b1f8108d198345…

MALICIOUS

PDF

71.0 KB Created: 2021-03-19 17:01:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: e548831c7c1cea4296979051156a2f79 SHA-1: 0ec7bd10f9d79c56001fad18402f77823865fa77 SHA-256: c4b1f8108d1983450771d34270307eecb26abca0a16324e46a93416fbf5c8656
186 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains a large number of external links, many hosted on disposable domains, suggesting a link farm or redirection scheme. The primary URL observed is `https://bologen.ru/wix?keyword=apush+chapter+39+key+terms`, which likely serves as an entry point to this network of sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://bologen.ru/wix?keyword=apush+chapter+39+key+terms PDF link annotation
    • https://rorobobadewa.weebly.com/uploads/1/3/1/1/131164171/vuwufobinus_buzasudizafek_jowasu.pdfIn PDF document text
    • https://disesusobabetom.weebly.com/uploads/1/3/0/8/130814900/4d2c1475c95.pdfIn PDF document text
    • https://bawoxuvebi.weebly.com/uploads/1/3/4/8/134886771/3102616.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4390684/normal_5fe9a95c8324c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4444096/normal_5fd317f44fb6f.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4380527/normal_5fc6a3d079cf7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4456376/normal_60377b6e2daff.pdfIn PDF document text
    • https://wiwazojuxosupud.weebly.com/uploads/1/3/1/3/131379189/jeveletiwa-sizamodexaxo-gejanuzaxud.pdfIn PDF document text
    • https://vonemiwez.weebly.com/uploads/1/3/0/7/130776812/lipajaka.pdfIn PDF document text
    • http://mugeziv.22web.org/mezalazeribap.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4451565/normal_5ffb86fbbd22a.pdfIn PDF document text
    • https://nepokotivo.weebly.com/uploads/1/3/2/8/132814168/2287535.pdfIn PDF document text
    • https://fiduludebiwoki.weebly.com/uploads/1/3/4/3/134317875/f288d8b47.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://2080fafa-2491-4ac3-8118-a138f33bff34.filesusr.com/ugd/822ecd_b2dd91da92d54fad8bb8b75ce99d8c4b.pdf?index=trueIn PDF document text
    • http://rupokabimizoju.rf.gd/40977085217.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3c4ae0df-b845-4fba-9d13-0c4047114713/mivojelavo.pdfIn PDF document text
    • https://299bc67c-4c9a-44ea-852c-18f2d39dca40.filesusr.com/ugd/954c8b_5e2947cc0bd64e15acf13077eb307162.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/d6c33aef-ba92-4762-9d10-c9dc589f88c6/silupabolefotim.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e62b4f49-60ae-4085-8eb0-a10187048ec2/present_continuous_tense_worksheet_grade_7.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e5ef606b-ae91-4105-9087-1acfc001545c/clasificacion_de_cuentas_por_tipo_naturaleza_y_saldo.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_off0000d939.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD939 5616 bytes
SHA-256: a4f9ecd1f0804a935c047f221b9b0299618676423baa9b208dc07fdec217cf53
font_01_sfnt_off0000ec2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC2A 10160 bytes
SHA-256: 1185bc580233ad6c27f2ba8790e947312b0c1af8f045c596f775ee6ac27ac940