Malicious PDF — malware analysis report

Static analysis result for SHA-256 8091dda1c7398989…

MALICIOUS

PDF

72.2 KB Created: 2021-09-20 00:57:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 38d5ab430e45b9c0fbc7235f3b8cd05e SHA-1: 1a7f376e01660a54e5f7991210d8113efd6031c1 SHA-256: 8091dda1c73989897094b49cefead9a9f2add87ddd286a1ef3a2c133502b93b3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to potentially compromised websites or disposable hosting. The document body is heavily obfuscated and contains no readable content, suggesting its primary purpose is to host these links rather than convey information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://singer-island-condos.com/userfiles/files/97871903392.pdf
    • https://chinese-wall.tw/upload/files/11694781734.pdf
    • https://tw-itemaos.com/ckfinder/userfiles/files/birapepojufozunas.pdf
    • http://www.peritaonline.es/ckfinder/userfiles/files/rukekelopavosineludo.pdf
    • http://cnsgawefgl.netsociality.com/upload/files/56362656269.pdf
    • https://holcom-wd.com/webroot/img/files/judagiworavupazirovi.pdf
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/2bjp6gc603b70qjabn095b3bh8/gemazifoliwenosusiz.pdf
    • https://nocnepal.org.np/ckfinder/userfiles/files/fipineneguvuxabuwajisiji.pdf
    • http://surausa.com/uploads/files/ledijeseduvowixuvuzev.pdf
    • http://esistore.com/userfiles/file/20316521319.pdf
    • http://romanasulcikova.cz/userfiles/wofusozizizexusoweruzi.pdf
    • https://nocenzura.space/web/img/podborky/files/54190001462.pdf
    • https://belitour.ir/basefile/belitourir/files/tujisirekagoweda.pdf
    • https://tnmkor.com/FileData/ckfinder/files/20210917_D836675A297AA6D7.pdf
    • http://hattrick-sports.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141d37bcc16a---jajolojoworunajetebu.pdf
    • http://jedzenie365.pl/ckfinder/userfiles/files/35811553502.pdf
    • http://roocenter.ru/upload/file/55925667767.pdf
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/0b0e35bc437be645fcf7ad01dc999a7e/pudazudinapixetowineme.pdf
    • http://shepardinteriordesign.com/rw/upload/file/13474104239.pdf
    • http://104408017.linker.tw/files/linulutobowasagedusebefo.pdf
    • http://bumsnab.ru/uploads/files/75241640158.pdf
    • http://gezond-trakteren.nl/kasteel-doornenburg-img/bestandenfile/temepobobilebu.pdf
    • http://esipro.lu/userfiles/file/bosaze.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=best+ios+zombie+survival+games
    • 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_off0000b82b.bin
47c4830d50420c4532e27975ff6784d7f29d0f617e4b4ee10edef18fa981a87d
pdf-font-stream PDF embedded font (sfnt) at offset 0xB82B 16448 bytes
font_01_sfnt_off0000e275.bin
1b5b3395579fa55c5bcd4cc7c4d2b5ee3cec533cfa705c83133e88d5f0f10ebc
pdf-font-stream PDF embedded font (sfnt) at offset 0xE275 10764 bytes
font_02_sfnt_off0000fb67.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xFB67 16792 bytes