Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b391fce67da5b7b…

MALICIOUS

PDF

102.1 KB Created: 2021-04-02 23:43:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: 5cc24486e234b25a8e54ffd7f5844ab9 SHA-1: cf76e3089c73923dc5e5511ba137c0752fedc033 SHA-256: 8b391fce67da5b7bbcc0cc2be13157fe63752deefe1d140f60f1e6e7eadeedf0
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to disposable hosting and likely part of an SEO link farm. The ClamAV detection and ML classifier strongly indicate malicious intent, specifically identified as a phishing trojan. The document body, though partially corrupted, suggests a lure related to 'worksheet answers', which is a common tactic for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://nipisod.ru/wix?keyword=chapter+5+absolute+monarchs+in+europe+worksheet+answers PDF link annotation
    • http://jurojegame.getenjoyment.net/ludosujup.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4371812/normal_6016cf95b8a88.pdfIn PDF document text
    • https://jewakazakiven.weebly.com/uploads/1/3/1/4/131437085/tofirakijobuwabipi.pdfIn PDF document text
    • https://lokamafurixese.weebly.com/uploads/1/3/4/5/134509290/lanomilekiwagu.pdfIn PDF document text
    • http://kojazunupetip.mygamesonline.org/sonusejorusel.pdfIn PDF document text
    • http://xemakaze.mywebcommunity.org/bekurumuw.pdfIn PDF document text
    • https://kokazokurazafan.weebly.com/uploads/1/3/5/3/135348127/koruni.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4380237/normal_60135dd7a627b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4478133/normal_605a920285c5a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4428342/normal_60143e50ca02f.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://7980b0ff-2efe-48f4-a442-6c87bca80713.filesusr.com/ugd/9bd8c3_62eb1a23cc73495c9f010c3c8ab11f3c.pdf?index=trueIn PDF document text
    • http://nakixaxev.myartsonline.com/python_chatbot_tutorial.pdfIn PDF document text
    • https://d4180a97-8dd0-4bf1-9e2f-d1b128d1a64d.filesusr.com/ugd/ae059d_b8bcdc42918549979c0a6ad8b00d5767.pdf?index=trueIn PDF document text
    • https://7095e710-59ac-4d27-8a5a-f3bbcaf65deb.filesusr.com/ugd/418e76_97627c9766cb48d28784761e737b17ad.pdf?index=trueIn PDF document text
    • https://254a6a59-343e-4b7e-907c-c4819e171fff.filesusr.com/ugd/decf6f_176568dfd43a467dbf6e82005bfd1338.pdf?index=trueIn PDF document text
    • https://6b52f5a6-db44-4d3e-8337-ab33c729cb13.filesusr.com/ugd/f4de5e_8f0f9b501248429599d24e5c86ff2518.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/vojapu/41261948954.pdfIn PDF document text
    • https://dcc20dec-0195-4543-b617-cfb82efd15f0.filesusr.com/ugd/30ea26_c60db1fcb5f34dec9d9fa2474d4ef6dd.pdf?index=trueIn PDF document text
    • https://329f26c8-0235-4118-8622-173d264d9cf1.filesusr.com/ugd/221f3a_dc0faeaf2cf64c55a5b2a7a6edd6eac5.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/fosagoba/sql_server_2012_standard_link.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_off000147d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x147D0 2828 bytes
SHA-256: 85b692c1c636aed9ab1240d2a7361179fdd6c0849396a06064984f922e967b4f
font_01_sfnt_off000151ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x151CA 5496 bytes
SHA-256: ccab27f2a932fdd7ef8d3a96538e772f0bd47db43fefe42428ae294e9e12a40b
font_02_sfnt_off0001645e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1645E 10232 bytes
SHA-256: 738a12b58d0a774573da61df9002de86da18ff6710021a0083a21bbd42e70363