Malicious PDF — malware analysis report

Static analysis result for SHA-256 31afc8bbe4d6517b…

MALICIOUS

PDF

76.6 KB Created: 2021-02-21 21:42:34 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: db2b2e368d713e81482dcefe32f4046b SHA-1: 9c598f3e2882df01675d5929ef0f35548ce38085 SHA-256: 31afc8bbe4d6517b565177fc3901ed28d40483a10fe7c86c3ded8368927bd664
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, suggesting a link farm or phishing operation. The ML classifier and ClamAV detection strongly indicate maliciousness. While no scripts were explicitly extracted, the PDF structure and embedded URLs point towards a malicious document designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • 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.
  • 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 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/strik?utm_term=star+trek+discovery+season+3+episode+8+reddit
    • https://jifilebipik.weebly.com/uploads/1/3/4/3/134375607/xutopejo.pdf
    • https://cdn.sqhk.co/pubodegosog/jb6hefk/sowuwelibofuf.pdf
    • https://rovagurepuj.weebly.com/uploads/1/3/1/8/131856033/a31ca.pdf
    • https://sutukedepebovi.weebly.com/uploads/1/3/4/7/134753024/piwopazebogunim-besib-linukuvo.pdf
    • http://dunetetemob.22web.org/37875181670.pdf
    • https://guxesawaxogego.weebly.com/uploads/1/3/4/3/134314991/bekawewu-donisef.pdf
    • https://static.s123-cdn-static.com/uploads/4368998/normal_5ff6098f8ec34.pdf
    • https://static.s123-cdn-static.com/uploads/4473031/normal_5feeeeb6274f9.pdf
    • https://cdn.sqhk.co/delojiwuguj/gjfigjH/war_of_the_worlds_two_the_challenge_cast.pdf
    • https://ripodomix.weebly.com/uploads/1/3/0/7/130775876/2280574.pdf
    • https://cdn-cms.f-static.net/uploads/4444655/normal_6023d4083a17b.pdf
    • https://cdn.sqhk.co/voravaxa/ijhehjO/telegram_definition_and_examples_of_oxymoron.pdf
    • http://xowefew.22web.org/article_of_association.pdf
    • https://gozaxuvo.weebly.com/uploads/1/3/4/6/134612917/c9e9089.pdf
    • http://xopapen.iblogger.org/chemistry_calorimetry_problems_worksheet.pdf
    • https://jopuwijexanubuf.weebly.com/uploads/1/3/0/8/130874501/b378b3.pdf
    • https://zulasiromeg.weebly.com/uploads/1/3/1/4/131453934/1891652d.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://bimivopi.epizy.com/backtrack_tutorial_francais.pdf
    • http://zusagijumetuze.epizy.com/38011481523.pdf
    • http://parisexubuvi.rf.gd/bebizakivanolulir.pdf
    • http://fegegarovepib.epizy.com/22363036906.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ec81.bin
ad13a77d1a95e87cab63b9b2768fbeb3bdab2e6ff6eb107b8bf4f0fbf87c1ae5		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEC81 5720 bytes
font_01_sfnt_off00010016.bin
18b2ea44aa1678f8acff47097c6c267ba65559d8d77796facfd64271e97d7512		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10016 10996 bytes

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