Malicious PDF — malware analysis report

Static analysis result for SHA-256 bdc21df5583feddc…

MALICIOUS

PDF

32.1 KB Created: 2020-08-19 22:47:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 1ee49f78ff79aa023a33a3d3edde6c4a SHA-1: c56ff125b7c3deb9fadf6ab1cafee10397e84076 SHA-256: bdc21df5583feddcbac3948e29f2d2977125e78bf3414f0677be3a5b2098889f
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains embedded links, with one specifically identified as a malicious redirector. The document body, though heavily obfuscated, contains text suggesting it is an 'answer key' for characterization exercises, which is a common lure. The PDF_MALICIOUS_REDIRECTOR_LINK heuristic confirms the presence of a link to known malicious infrastructure, and the ML classifier strongly indicates maliciousness. The primary attack vector appears to be a social engineering lure to redirect the user to a malicious site.

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=direct+and+indirect+characterization+exercises+answer+key
    • http://ratudeku.himleycc.co.uk/uploads/1/3/1/4/131438366/gabikov.pdf
    • https://cdn.shopify.com/s/files/1/0440/7282/9078/files/14283948480.pdf
    • https://cdn.shopify.com/s/files/1/0433/1739/5611/files/fun_guided_reading_activities_ks2.pdf
    • https://cdn.shopify.com/s/files/1/0433/2906/1014/files/25206960487.pdf
    • https://cdn.shopify.com/s/files/1/0430/7212/7125/files/mapa_geologico_da_bahia.pdf
    • https://cdn.shopify.com/s/files/1/0429/2149/2643/files/antisocial_personality_disorder_treatment_plan.pdf
    • https://cdn.shopify.com/s/files/1/0430/0200/3615/files/converting_length_units_worksheet.pdf
    • https://cdn.shopify.com/s/files/1/0433/2696/3865/files/kojoderuval.pdf
    • https://cdn.shopify.com/s/files/1/0434/3873/5517/files/freda_gatz_shots_fired.pdf
    • https://cdn.shopify.com/s/files/1/0460/1351/3889/files/67618972525.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/32506959796.pdf
    • https://cdn.shopify.com/s/files/1/0434/3929/2577/files/98821550528.pdf
    • https://cdn.shopify.com/s/files/1/0429/8866/7033/files/44741982938.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000042d3.bin
29e4216f8005f4bcaaec77a62a8b93473af081ae74e133097c269c8f8343db54
pdf-font-stream PDF embedded font (sfnt) at offset 0x42D3 5368 bytes
font_01_sfnt_off0000552a.bin
b36a9a9f7bb9a2865eeed5125b16f0094810103e0a23934fee5e21f745b28a09
pdf-font-stream PDF embedded font (sfnt) at offset 0x552A 8812 bytes