Malicious PDF — malware analysis report

Static analysis result for SHA-256 87b4313aaefa1932…

MALICIOUS

PDF

95.7 KB Created: 2021-05-21 03:41:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f461ef86b6b449979e8cbeab1592d57a SHA-1: 7d3043781675d1434a74013cef9a398ea90b316c SHA-256: 87b4313aaefa1932bf2b2e4d3237b9421fd04e5291829efd8174c7a6aa7210c5
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are to benign-looking PDFs, but one prominent URL, 'https://xezojetit.ru/strik?utm_term=substitution+method+examples', is flagged as suspicious and likely malicious. The ML classifier and ClamAV detection strongly indicate malicious intent, classifying it as a phishing or trojan PDF. The document body, though heavily garbled, suggests a theme related to 'substitution method examples', which is likely a lure to disguise the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

Heuristics 5

  • 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
  • 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://xezojetit.ru/strik?utm_term=substitution+method+examples
    • https://cdn-cms.f-static.net/uploads/4425256/normal_60156c613df93.pdf
    • https://cdn-cms.f-static.net/uploads/4421056/normal_605aa64f92dbc.pdf
    • https://pulamawuba.weebly.com/uploads/1/3/0/8/130873907/samira.pdf
    • https://tofaxewa.weebly.com/uploads/1/3/4/6/134672655/vukuzuja.pdf
    • https://vinixojaz.weebly.com/uploads/1/3/5/3/135312356/fuxobesazevali.pdf
    • https://static.s123-cdn-static.com/uploads/4474449/normal_5fceb3303afd0.pdf
    • https://cdn-cms.f-static.net/uploads/4482418/normal_6038ea9e810b1.pdf
    • https://fegemuvu.weebly.com/uploads/1/3/2/6/132695633/xobulu.pdf
    • https://sedozexejelem.weebly.com/uploads/1/3/1/8/131871533/pisuzuselitalivof.pdf
    • https://valojeruxul.weebly.com/uploads/1/3/4/6/134681631/116c3b71.pdf
    • https://rixutabenenik.weebly.com/uploads/1/3/4/4/134498467/b1887.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://s3.amazonaws.com/wazorixekunafob/open_puzzle_box_level_24_answer.pdf
    • https://s3.amazonaws.com/wifukedot/dragon_city_double_flame_dragon_breeding_guide.pdf
    • https://s3.amazonaws.com/tugafebip/tencent_gaming_buddy_beta_free_fire.pdf
    • https://s3.amazonaws.com/xefezesebusu/81467136100.pdf
    • https://s3.amazonaws.com/wonumafubij/66518148632.pdf
    • https://s3.amazonaws.com/jopomodilamego/where_to_purchase_singer_4423_sewing_machine.pdf
    • https://uploads.strikinglycdn.com/files/4b9bcb29-61b9-45f7-925d-2ae3ef4d3fc3/what_is_a_lookbook_in_film.pdf
    • https://s3.amazonaws.com/jivala/kazowibab.pdf
    • https://s3.amazonaws.com/xuzed/xaxapovexafibadenur.pdf
    • https://s3.amazonaws.com/zerejibixupav/codeword_barbelon_danger_in_the_vatican.pdf
    • https://s3.amazonaws.com/mamibis/repezovuv.pdf
    • https://uploads.strikinglycdn.com/files/6a633cd0-4d3b-4cb1-acff-4c97a1e92273/html_css_table_alternate_row_color.pdf
    • https://uploads.strikinglycdn.com/files/429babf1-bc47-4553-9a41-56c86af8a76c/xelapim.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012c6b.bin
0eb5a5ee1439b82930bcc628f7b6d4578da3da84be65310c940f5c9b97d5f373
pdf-font-stream PDF embedded font (sfnt) at offset 0x12C6B 5296 bytes
font_01_sfnt_off00013e2f.bin
48db6011c7e30775abb0834a0f18e912496706523641d80bfd32b4eb628789f0
pdf-font-stream PDF embedded font (sfnt) at offset 0x13E2F 10860 bytes
font_02_sfnt_off00016325.bin
a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f
pdf-font-stream PDF embedded font (sfnt) at offset 0x16325 4324 bytes