Malicious PDF — malware analysis report

Static analysis result for SHA-256 21c952d6b1c88737…

MALICIOUS

PDF

72.7 KB Created: 2021-04-12 12:12:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: c88cefee10ddd18356866204f602881c SHA-1: 2eee8edc21c95f1cefba6ddd3e89b44808e82abf SHA-256: 21c952d6b1c88737b65eeffbcd705df10d2547ac1381dcfabc4d6871a65ccc67
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a phishing or trojan threat. It contains numerous embedded URLs, many pointing to disposable domains, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated, but the presence of external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly suggest a phishing or malware distribution attempt.

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://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdf In PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/29579557159.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/dupoxemijuwavamuvugorudiz.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/jedirokadezat.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/4264017636.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/loboje.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/75468476758.pdfIn PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/kimakevenowafuxopepasu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=etfs+for+dummiesPDF link annotation
    • https://lib.asu.edu/system/files/webform/61431168480.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/83703622856.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/roporopapoviz.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/xegenaxug.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d15f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD15F 4544 bytes
SHA-256: b9d7754144fafeb4c8ffe5253a3fc5e2920c5558bd7cb0117dfd5901819c93ea
font_01_sfnt_off0000e0d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0D0 11468 bytes
SHA-256: 273c4a97a858d648de5f11e7fee753bb5a9886ee6c0e44c9c606f2b23e4858fb
font_02_sfnt_off000107e6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107E6 4324 bytes
SHA-256: 1158d95dac44631f497756703988ba3645251422e7ff0015d3fca430225e7c3e

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