Malicious PDF — malware analysis report

Static analysis result for SHA-256 7df6dae52de66fb7…

MALICIOUS

PDF

76.7 KB Created: 2021-04-16 09:46:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8cb4913453d703ab7e9db7f9f2f66e11 SHA-1: ebd957a2d19ec368c47ca425d242234156218ed6 SHA-256: 7df6dae52de66fb762bb84e447c244c77f0b2c232c65c60ac9a1d415e2447b17
126 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. The document body, though heavily obfuscated, suggests a lure related to 'worksheet answers'. Several embedded URLs point to potentially malicious or unknown domains, with one specifically identified as a link farm on disposable hosting, indicating a likely phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://klm3fg.grhosting.cz/sites/default/files/webform/files/wajuso.pdf
    • https://www.uts.cw/sites/default/files/webform/nukuromenalifaru.pdf
    • https://ambrose.edu/sites/default/files/webform/71048230710.pdf
    • https://www.jsif.org/sites/default/files/webform/vinuriruxelapaviwona.pdf
    • https://ambrose.edu/sites/default/files/webform/fabifuturofutip.pdf
    • https://www.enwidth.com/sites/default/files/webform/resumes/lerudaxalopavowurugepoviw.pdf
    • http://russian-ice-spb.ru/sites/default/files/webform/files/fapulewamekunasu.pdf
    • https://vectorcorp.net/sites/default/files/webform/resume/30106672217.pdf
    • http://www.friendlycc.com/sites/default/files/webform/98819861428.pdf
    • https://www.uts.cw/sites/default/files/webform/47116150145.pdf
    • http://www.friendlycc.com/sites/default/files/webform/topevonizudurazot.pdf
    • https://www.a1touchsolution.nl/sites/default/files/26511902049.pdf
    • https://web.liderpapel.com/sites/default/files/webform/xikamiwaboloz.pdf
    • https://www.ofalloncasting.com/sites/default/files/webform/tirudekamevajoluzagobumi.pdf
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/84972388600.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=transformation+of+trig+functions+worksheet+answers
    • https://thesanfordschool.asu.edu/sites/default/files/webform/xumigisapiwonatidokababup.pdf
    • https://minorsoncampus.princeton.edu/system/files/webform/posilo.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000da23.bin
0ac50f916485d8f7711671ce547c638525144e31d8bb1e084c94f0211b611984		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDA23 5248 bytes
font_01_sfnt_off0000ebe2.bin
434549745713e55990d9277a30933126d915dfdd0cc646d50f0fff661b549c5e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEBE2 12876 bytes
font_02_sfnt_off00011771.bin
4fcfa7c68d76e23b667942a3ac892d2d5d88346478daafc61479ad4df4af3dd3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11771 4324 bytes

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