Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8523ba3258e257e…

MALICIOUS

PDF

77.4 KB Created: 2021-04-05 09:31:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-10
MD5: 42984020f2992db38024485a02d360d4 SHA-1: 5646c293da9fcda4ac24ce6c93e782291841582e SHA-256: a8523ba3258e257e66bf0c8abb1659ebf0d08e920ece518915a60bf266dd8b0e
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of external links, many of which point to disposable hosting services, indicating a link farm designed for SEO manipulation or phishing. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution through these links. The document body, though heavily obfuscated, contains keywords related to a textbook download, reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://bologen.ru/wix?keyword=physics+10th+edition+cutnell+pdf+download PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4467007/normal_6069761654113.pdfIn PDF document text
    • https://benerema.weebly.com/uploads/1/3/1/4/131408328/a4e3473.pdfIn PDF document text
    • https://monemoret.weebly.com/uploads/1/3/4/6/134667898/tisev.pdfIn PDF document text
    • http://pugisapi.mypressonline.com/lefapozizusajesopixen.pdfIn PDF document text
    • http://vosojivaru.mypressonline.com/59166991332.pdfIn PDF document text
    • https://wokogosomexar.weebly.com/uploads/1/3/5/3/135322546/646de353.pdfIn PDF document text
    • http://pedosapabosa.iblogger.org/tutofevifeselitub.pdfIn PDF document text
    • http://gofadivus.mygamesonline.org/o_que__balanced_scorecard.pdfIn PDF document text
    • https://kekisuganuzab.weebly.com/uploads/1/3/4/7/134721312/a4165429f91d5e.pdfIn PDF document text
    • https://gisoroweri.weebly.com/uploads/1/3/4/8/134893792/zetopajazesivu.pdfIn PDF document text
    • https://mewejubakokexal.weebly.com/uploads/1/3/2/6/132681976/rixixun.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421788/normal_5fd97ff12b750.pdfIn PDF document text
    • https://boxatikavizag.weebly.com/uploads/1/3/4/6/134680825/salogajose.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4475204/normal_602a0a09da60a.pdfIn PDF document text
    • https://leruvipox.weebly.com/uploads/1/3/5/3/135347136/ce571dffa875.pdfIn PDF document text
    • https://xigujevaw.weebly.com/uploads/1/3/4/7/134701692/61c5b36bc8b91fd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423166/normal_6034100c79826.pdfIn PDF document text
    • http://rafupofamurawaf.mygamesonline.org/37394563065.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://dilizefolu.rf.gd/melanoma_nccn_guidelines_2018.pdfIn PDF document text
    • https://s3.amazonaws.com/baposivarabuj/fejosobarobibofinu.pdfIn PDF document text
    • http://mudozegiviw.epizy.com/dibana.pdfIn PDF document text
    • https://s3.amazonaws.com/pexodugosa/hamlet_1996_full_movie_free_download.pdfIn PDF document text
    • https://s3.amazonaws.com/xetasif/balanemub.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_off0000eff5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFF5 5536 bytes
SHA-256: f38637a06cc2a2ebfa7a5633d34b3d4a83e8c16ec933f5f5399a8c75c9a1feb5
font_01_sfnt_off000102e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102E9 10568 bytes
SHA-256: d0374018eeb63286c0f5a703c2b5c520e812e2c2f5f62d2720314fd5099e02ae