Malicious PDF — malware analysis report

Static analysis result for SHA-256 a18f389558ebd997…

MALICIOUS

PDF

89.5 KB Created: 2021-03-17 05:40:34 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: f5c386ae0464932c09971bcb11709faf SHA-1: b0f3d8ae28ca1805470ff85d5f85fd374fed788e SHA-256: a18f389558ebd99755128f1862589197e2a6066fc9c4897e862bb69a00fa6092
134 Risk Score

Malware Insights

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

The file is identified as a malicious PDF by multiple heuristics, including a critical ClamAV detection and an ML classifier. It contains numerous external URIs, with a primary focus on downloading content from 'zajinet.ru' and 'naliputa.mywebcommunity.org'. The PDF appears to be a link farm, attempting to disguise its malicious intent by presenting itself as a document related to educational materials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://zajinet.ru/wix?keyword=dynamic+korean+workbook+1+answers+pdf PDF link annotation
    • http://naliputa.mywebcommunity.org/16118959089.pdfIn PDF document text
    • http://vomidujoma.scienceontheweb.net/gipuzokika.pdfIn PDF document text
    • https://datulexajolibup.weebly.com/uploads/1/3/0/7/130738708/d2a2a7ba05a057.pdfIn PDF document text
    • http://nakalabaxis.mywebcommunity.org/can_you_really_make_someone_fall_in_love_with_you.pdfIn PDF document text
    • http://gopusoduj.mygamesonline.org/15198249622.pdfIn PDF document text
    • https://nizevamil.weebly.com/uploads/1/3/2/8/132814567/tufitojirezofag.pdfIn PDF document text
    • http://zokazurimila.mygamesonline.org/real_estate_agent_pre_license_course.pdfIn PDF document text
    • http://muzumekowasisig.iblogger.org/strategic_thinking_in_business.pdfIn PDF document text
    • http://noninegu.22web.org/el_nombre_de_la_rosa_pelicula_completa_en_castellano_umberto_eco.pdfIn PDF document text
    • http://tunapobene.22web.org/sql_server_tutorial_kudvenkat_blog.pdfIn PDF document text
    • http://zeriwegitesokom.iblogger.org/blind_man_s_bluff.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://xatabiraluxuded.rf.gd/zujovugatimu.pdfIn PDF document text
    • http://pibusobi.epizy.com/watolazubikojasejev.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4f3e84fb-3e33-4fa9-9c6c-a1005c5c35d1/69399236916.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/58f0709f-48f8-444f-9e2e-a3e05ebeeac7/lexaxovelukabexezumomiru.pdfIn PDF document text
    • http://sulumasofip.epizy.com/92706909509.pdfIn PDF document text
    • http://kugixuxekut.rf.gd/41032559107.pdfIn PDF document text
    • http://fubolorira.epizy.com/love_after_love_poem.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c24cea65-5e67-49bd-ad33-afba7c06c415/pifol.pdfIn PDF document text
    • http://xofaxozewodaf.rf.gd/treble_clef_bass_clef_worksheet.pdfIn PDF document text
    • http://zejekaliv.epizy.com/kojawivawufipegumepiwemod.pdfIn PDF document text
    • http://rurubafemiw.rf.gd/horizontal_progress_bar_android_studio.pdfIn PDF document text
    • http://jalugegaru.epizy.com/senisasovisojobejeranap.pdfIn PDF document text
    • http://vudafudilisa.epizy.com/judezisar.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF95 14612 bytes
SHA-256: cf56a69ada97eea7dffd03f909276c6520d1b6fa7bbeb0ffbd56a01dda716202
font_01_sfnt_off00011c8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C8D 5716 bytes
SHA-256: c922ec96a203469da67c1ed281588cff2a76b500d24381050b672821b685fc57
font_02_sfnt_off00013016.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13016 11752 bytes
SHA-256: d278d8dcb855438ed031872d8a048f5429a5a541459e5618b189cca95bbe191d