Malicious PDF — malware analysis report

Static analysis result for SHA-256 12dbf311b5900c5f…

MALICIOUS

PDF

76.5 KB Created: 2021-09-16 07:11:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 34b870c9b6190a8fd73d0ff2ed20a876 SHA-1: 0ca95772667292571705f6c5eb22c8d7868e351c SHA-256: 12dbf311b5900c5ff5bf4548369e2c9be8b645e8dcd8b8b3e609cf4715ebec19
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, with a critical heuristic firing for PDF_SEO_DISPOSABLE_LINK_FARM. This indicates the PDF is part of a link farm, likely intended to redirect users to malicious sites. While no scripts were explicitly extracted, the PDF structure and heuristics suggest it's designed to facilitate initial access via spearphishing, leading to further compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://healthywithhart.com/res/file/teworuzepojudadiwozonev.pdf
    • https://www.htlexpress.com/ckfinder/userfiles/files/65916875526.pdf
    • http://autowassenindex.nl/images/uploads/23640999859.pdf
    • http://enotecagaribaldi.it/userfiles/files/92958379639.pdf
    • http://zhongjiukeji.com/upload_fck/file/2021-9-16/20210916002416770164.pdf
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/161429d2492970---bowelanegisuro.pdf
    • http://kezheng.net/Upload/file/rivinobuxuk.pdf
    • http://tc-antey.ru/uploads/files/tojoketudozegafipesatitav.pdf
    • http://zanethompson.com/userfiles/file/robomiwimof.pdf
    • http://isspskola.lv/userfiles/files/10163160538.pdf
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/05ff291f8ccfd15aa20e2d75bac1ef6e/17506471172.pdf
    • https://hgqq.hk/tony/churchofgod/ckfinder/userfiles/files/zevijukugolebuke.pdf
    • http://skonasystems.com/userfiles/file/75305414026.pdf
    • https://grafconsulting.pl/Upload/file/26947064614.pdf
    • https://renesens21.com/ressources/upload/files/41732138665.pdf
    • https://noddy.nu/images/file/sinonapezunasinifite.pdf
    • https://accesoriosalmayor.com/images/userfiles/file/zutuduxumun.pdf
    • https://xtremefitness.com.au/application/third_party/ckfinder/userfiles/files/38506214167.pdf
    • http://phutungvespaco.com/luutru/files/xedukowevuxomiziregixu.pdf
    • http://101balkon.ru/upload/files/jozijugemisisi.pdf
    • https://istanbulbalbir.com/upload/ckfinder/files/75414495079.pdf
    • https://pasationtravellers.com/root/FCKeditor/file/bazigatuwogidedo.pdf
    • https://ms2oke.com/contents/files/lakofeze.pdf
    • http://physio-praxismitte.de/userfiles/30116833332.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=game+ppsspp+naruto+impact
    • 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://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c06a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC06A 16792 bytes
font_01_sfnt_off0000d881.bin
d03ac27c60c92a7856a3ede0a2f775be0916105937984fe1de14ea29f39b7880		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD881 10628 bytes
font_02_sfnt_off0000f0cf.bin
988961a095d6ad97d8e10cc5b4c80499ace17f0d681f1d7121b98caca806cdf0		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF0CF 19828 bytes

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