Malicious PDF — malware analysis report

Static analysis result for SHA-256 66884e04e598839f…

MALICIOUS

PDF

40.0 KB Created: 2020-08-20 10:36:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 6be5d1c0b190f8c7a963162bc8828a75 SHA-1: 31a44ecd78cb972782ce73e45aaa3f50926b3203 SHA-256: 66884e04e598839f3e8ed6b271193cc0d3c4b239fc499bf0dcae9c2f570950fc
154 Risk Score

Malware Insights

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

The PDF contains embedded links, one of which points to a known malicious redirector. The document body, though heavily obfuscated, contains text suggesting it is a worksheet, which is a common lure. The presence of numerous other PDF links, many benign, suggests a link farm tactic to obscure the malicious destination. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://ttraff.cc/pify?keyword=fraction+word+problems+worksheet+for+grade+5
    • http://files.northposeybasketball.com/uploads/1/3/2/6/132696112/pamokidorozix.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://cdn.shopify.com/s/files/1/0435/3294/3519/files/puppy_dog_pals_colouring_sheets.pdf
    • https://cdn.shopify.com/s/files/1/0429/6572/9429/files/9th_class_chemistry_viva_questions_with_answers.pdf
    • https://cdn.shopify.com/s/files/1/0437/2814/2501/files/bukunogivasijumuzozibax.pdf
    • https://cdn.shopify.com/s/files/1/0432/1827/2417/files/78964684077.pdf
    • https://cdn.shopify.com/s/files/1/0434/0708/1622/files/1-_99_mining_rs3.pdf
    • https://cdn.shopify.com/s/files/1/0430/4322/5751/files/16213073463.pdf
    • https://cdn.shopify.com/s/files/1/0433/6844/8152/files/rajakavek.pdf
    • https://cdn.shopify.com/s/files/1/0432/4173/4301/files/551640754.pdf
    • https://cdn.shopify.com/s/files/1/0434/4204/5089/files/behka_re_audio_song.pdf
    • https://cdn.shopify.com/s/files/1/0435/4818/0634/files/34515033594.pdf
    • https://cdn.shopify.com/s/files/1/0429/9853/0202/files/2_digit_by_1_digit_multiplication_worksheets_grade_2.pdf
    • https://cdn.shopify.com/s/files/1/0438/8398/7096/files/grammar_for_english_language_teachers_2020.pdf
    • https://cdn.shopify.com/s/files/1/0431/0161/8327/files/fedanej.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_off00005d68.bin
fd6d7be97ed1e7523544de7412dc08a021592e578078503c969b284aeff0f5a5
pdf-font-stream PDF embedded font (sfnt) at offset 0x5D68 5944 bytes
font_01_sfnt_off0000718a.bin
e50dc02753beb20d47772977b2dfdac9e30af714c6c63ea8f7e064b674925d91
pdf-font-stream PDF embedded font (sfnt) at offset 0x718A 9860 bytes