Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b5e4e9333cec6c4…

MALICIOUS

PDF

77.0 KB Created: 2020-11-25 22:43:55 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 4bb7b0790741882a9115782a145210cc SHA-1: d1872a969402e4951180601e292ce5cc6dcb31d4 SHA-256: 5b5e4e9333cec6c4dc07f8832113bf09259696146e4dfce085c2e84deffd2568
156 Risk Score

Malware Insights

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

The PDF file contains heuristics indicating it is a link farm and has been flagged as malicious by ML classifiers and ClamAV. The document body, though partially garbled, suggests a lure related to an 'answer key'. The primary malicious URL, 'https://trafftec.ru/123?utm_term=additional+80+proportional+relationships+answer+key', is likely used to distribute a second-stage payload. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://trafftec.ru/123?utm_term=additional+80+proportional+relationships+answer+key
    • https://vaxajiwozoli.weebly.com/uploads/1/3/1/6/131637631/7510829.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/paropabaru/proform_treadmill_330x_maintenance_manual.pdf
    • https://s3.amazonaws.com/simujix/73488614355.pdf
    • https://uploads.strikinglycdn.com/files/97b9ce22-8b30-4617-9b43-e8c0fa1fb572/91250442706.pdf
    • https://s3.amazonaws.com/fekaduvopigab/92842318795.pdf
    • https://s3.amazonaws.com/vizegemawokaxe/episode_guide_this_is_us.pdf
    • https://s3.amazonaws.com/pirofopafu/bullet_holes_vector_free.pdf
    • https://s3.amazonaws.com/lovetijif/zubuxuz.pdf
    • https://s3.amazonaws.com/dowavelaxam/ashokan_farewell_violin_duet.pdf
    • https://s3.amazonaws.com/vokeri/kalegajaxuzadunomuw.pdf
    • https://s3.amazonaws.com/kigavanus/caracteristicas_de_la_celula_bacteriana.pdf
    • https://s3.amazonaws.com/gofilafixu/kaththi_tamil_movie_hd.pdf
    • https://s3.amazonaws.com/votawawo/3rd_grade_compound_words_worksheets_printable.pdf
    • https://s3.amazonaws.com/wipotegadodorek/csv_to_md_table.pdf
    • https://s3.amazonaws.com/lulelepese/boat_propeller_design_software.pdf
    • https://s3.amazonaws.com/belopudevuzuza/divukoto.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_off0000eca4.bin
96c8d584623bce426e673afd1ae29ba01a7dfbceca95405987e73def69e4f5d7
pdf-font-stream PDF embedded font (sfnt) at offset 0xECA4 5632 bytes
font_01_sfnt_off0000ffda.bin
cca8b3da1784fb03f70d55a2379d6799cb391d6b5734aae7bc94883a17edd2df
pdf-font-stream PDF embedded font (sfnt) at offset 0xFFDA 11440 bytes