Malicious PDF — malware analysis report

Static analysis result for SHA-256 a699b9b1ba970df8…

MALICIOUS

PDF

77.5 KB Created: 2021-01-11 12:13:51 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: f902087226592148898f386b94342ef8 SHA-1: ea108c138a7d923ea655063c64003bcb28300d30 SHA-256: a699b9b1ba970df830014f44e9e34fb723655b143d20f98d0900f8369cdeaf5e
192 Risk Score

Malware Insights

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

The PDF contains multiple links to disposable hosting, with one specifically identified as a malicious redirector. The document body, though heavily obfuscated, contains text related to an 'admit card' and the authoring application 'wkhtmltopdf', suggesting a lure to download a malicious file or visit a phishing site. The presence of embedded URLs and the ML classifier's high confidence score further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://traffmen.ru/aws?utm_term=scert+assam+admit+card In PDF document text
    • https://cdn-cms.f-static.net/uploads/4368489/normal_5fd660c061fe6.pdfIn PDF document text
    • https://site-1168144.mozfiles.com/files/1168144/virtual_villagers_origins_2_lavastone_cheat_xbox_one.pdfIn PDF document text
    • https://site-1175201.mozfiles.com/files/1175201/big_big_baller_mod_apk.pdfIn PDF document text
    • https://site-1167931.mozfiles.com/files/1167931/tovobapijanamomu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416789/normal_5f996f9d8488f.pdfIn PDF document text
    • https://cdn.sqhk.co/lugizumevemu/e4giQf4/51306381808.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4386354/normal_5fb7acd285226.pdfIn PDF document text
    • https://site-1178602.mozfiles.com/files/1178602/gukabepajanixexekonagi.pdfIn PDF document text
    • https://cdn.sqhk.co/lilomovetum/BvQhhHl/forupanepabusujiv.pdfIn PDF document text
    • https://riwominejakubik.weebly.com/uploads/1/3/4/5/134598273/ea7645.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4460072/normal_5feb2b7cb6ae2.pdfIn PDF document text
    • https://site-1166680.mozfiles.com/files/1166680/rurukubevibigonimokobomut.pdfIn PDF document text
    • https://site-1173386.mozfiles.com/files/1173386/8902145181.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f2a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2A2 5156 bytes
SHA-256: e24c20472ff71c36ebdd6093c9dfc4db3b472fd895b1a95aefa8a16305663860
font_01_sfnt_off00010410.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10410 10844 bytes
SHA-256: 48ad97485dd3e4a92cbc35d9e666c68908b9f284973da68675560559206c581f

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