Malicious PDF — malware analysis report

Static analysis result for SHA-256 3992d8a20c36fd07…

MALICIOUS

PDF

82.0 KB Created: 2021-03-23 23:50:09 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: e4c5d677cd96fc4e1a6f38c8f3da4fc9 SHA-1: 5c43dec2194a713ab5dca0cf882602a161c6887a SHA-256: 3992d8a20c36fd075081c2741d23d774190370e46e8a69bcc2fcf2e9dca2972a
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, many pointing to disposable domains, suggesting a link farm or SEO poisoning tactic. One prominent URL, 'https://jacksth.ru/wix?keyword=eoc+biology+study+guide+answers', indicates a lure related to study guide answers. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the PDF structure itself is used to host a large number of external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://jacksth.ru/wix?keyword=eoc+biology+study+guide+answers PDF link annotation
    • https://cdn.sqhk.co/rasepotobami/qbEiaha/rebotoduvurinoxike.pdfIn PDF document text
    • http://juzufezike.mygamesonline.org/korisodarubo.pdfIn PDF document text
    • https://cdn.sqhk.co/gibuzini/cieO2gg/32433790055.pdfIn PDF document text
    • https://wuwotozon.weebly.com/uploads/1/3/4/3/134315251/5456250.pdfIn PDF document text
    • http://xebiniseba.mygamesonline.org/bsc_mathematics_syllabus_madras_university.pdfIn PDF document text
    • https://cdn.sqhk.co/wedegetuso/hcQVjaP/toggle_key_meaning_in_computer.pdfIn PDF document text
    • https://kinanufojakosek.weebly.com/uploads/1/3/4/3/134350472/posoguzobotiz.pdfIn PDF document text
    • http://kitixukizogutik.mygamesonline.org/wabuvebipisi.pdfIn PDF document text
    • https://jukafubu.weebly.com/uploads/1/3/0/8/130874261/lemutawumoza_magadavenefu.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/jajoxulabojaso/briggs_and_stratton_pressure_washer_pump_oil_change.pdfIn PDF document text
    • https://1c019786-7048-4615-837a-ae53f087c4ae.filesusr.com/ugd/8b4172_3313d4afbf8541e3930df15fdede8033.pdf?index=trueIn PDF document text
    • https://35548484-ce42-4b18-9d9d-834326683263.filesusr.com/ugd/a221b6_7a8fa22b41aa4bf58a71f8a4b0d91412.pdf?index=trueIn PDF document text
    • https://5e54824a-8208-41b0-8aeb-7c017e8cfb46.filesusr.com/ugd/f64db8_34e4b6649f974b92aaf68d947121d599.pdf?index=trueIn PDF document text
    • https://43a2ba88-5de9-465b-b95f-6a4d82f2d06e.filesusr.com/ugd/dcbeda_833b304215dd4a3cb23ccf04816cc647.pdf?index=trueIn PDF document text
    • https://e691ad07-92dc-45fa-af10-8929b4045ede.filesusr.com/ugd/87b9a8_2c2e62dec2b04a49a051e0b0e3e76d6e.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/kelageketisefuv/mukafenebekapagonaxo.pdfIn PDF document text
    • https://6129906d-bc82-46a7-99f5-71793a58af3c.filesusr.com/ugd/d162e3_b5e43338f3004bec8b6961b5862c1660.pdf?index=trueIn PDF document text
    • https://78151a86-a557-4e49-81aa-a2539eea45c7.filesusr.com/ugd/204f4f_a5889d814e7340ada54ec3ebb1f6ca40.pdf?index=trueIn PDF document text
    • https://7f06b679-e14d-4525-8955-d56a7cf6f710.filesusr.com/ugd/79e5df_53582a1f83ba4f2ea5757894013c7484.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/regovadeje/46814912249.pdfIn PDF document text
    • https://s3.amazonaws.com/miwolezedubujoz/79942173400.pdfIn PDF document text
    • https://2d841ef3-a248-4e6a-996b-2d54d6713fdd.filesusr.com/ugd/1decf9_0ed8aab1e0234fdcbfc225bd0d51f1a7.pdf?index=trueIn 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_off0000ff32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF32 5400 bytes
SHA-256: 0044b51c401349cd7053226151ca3aee30c2ada4e673c0541ffb823e390817e5
font_01_sfnt_off000111b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111B4 12076 bytes
SHA-256: 71eb89b30ef6c54e16a552e4d7a90638d6f71e0edc7cbb714792da341f2cf26b