Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4fe20ce4c2dd455…

MALICIOUS

PDF

74.4 KB Created: 2021-03-22 08:51:30 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: a83413cca8483b34098606618bf0e819 SHA-1: 20637c7062a3f408e7a7cf93cc643f36de62def8 SHA-256: c4fe20ce4c2dd455eb5a3ec241df631de7543dd882b86b4ad26fed4cf2037148
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or malware distribution attempt. It contains numerous external URIs, with a primary suspicious URL being https://nipisod.ru/strik?utm_term=volume+of+triangular+prisms+worksheet+pdf, suggesting a lure to a malicious site. The document body is heavily obfuscated, but the presence of embedded URLs and the overall structure point towards a malicious intent, likely to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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://nipisod.ru/strik?utm_term=volume+of+triangular+prisms+worksheet+pdf PDF link annotation
    • http://rkconstructionsucks.com/basic_civil_engineering_book_free8xs41.pdfIn PDF document text
    • http://lomigakorak.getenjoyment.net/timug.pdfIn PDF document text
    • http://zunuruxeguxifi.mygamesonline.org/lenewukikexesigezezi.pdfIn PDF document text
    • http://wogivodugakovek.mygamesonline.org/9.pdfIn PDF document text
    • http://zusagukitu.mywebcommunity.org/oci_registration_form.pdfIn PDF document text
    • http://prizinsta365.online/pemusofujolajoxetaborzzfgz.pdfIn PDF document text
    • http://pipvip.ru/collective_and_abstract_nouns_exercisesmrs7q.pdfIn PDF document text
    • http://juwupexutaval.mywebcommunity.org/bodyweight_training_plan.pdfIn PDF document text
    • http://rexuwoxaga.sportsontheweb.net/42174248066.pdfIn PDF document text
    • http://fukazab.mywebcommunity.org/83287981838.pdfIn PDF document text
    • http://navevukosuso.mypressonline.com/keurig_b145_office_pro_parts.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/minegikukovel/cells_and_tissues_anatomy_and_physiology.pdfIn PDF document text
    • http://difavaxegugadu.epizy.com/mansions_of_madness_expansion.pdfIn PDF document text
    • http://rabelinowizufe.myartsonline.com/92404479958.pdfIn PDF document text
    • http://botuwosolu.rf.gd/65656191906.pdfIn PDF document text
    • http://solazagu.epizy.com/20596663969.pdfIn PDF document text
    • http://pepagipil.epizy.com/lirobedirexevadofezisawa.pdfIn PDF document text
    • http://jagomizaf.atwebpages.com/botanica_sistematica_darwin_rueda.pdfIn PDF document text
    • https://s3.amazonaws.com/tarajix/scrabble_word_finder_dictionary_free.pdfIn PDF document text
    • https://s3.amazonaws.com/viwoxuz/jabonikiwolomuwe.pdfIn PDF document text
    • http://lipabarud.atwebpages.com/ccna_voice_portable_command_guide_free_download.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_off0000e55a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE55A 5576 bytes
SHA-256: 650a2f90294039c4081ba6e99900d23821d0b25378b76ae5d24f9ecfcf056ada
font_01_sfnt_off0000f83e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF83E 10612 bytes
SHA-256: 4d296782297dcb5a4cc22aa3ac33d9d37f8a247318642fbc7ed54b99bc920081

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