Malicious PDF — malware analysis report

Static analysis result for SHA-256 83d7323b64a6ef09…

MALICIOUS

PDF

86.6 KB Created: 2021-07-06 23:43:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 8961fae55b546d392b7fa07a893bc530 SHA-1: d8180de225124432e24b795b74302eea66d819b0 SHA-256: 83d7323b64a6ef09a7e0f1d753fe43611a253860503d5df6e4ff5e0d767aa5e2
164 Risk Score

Malware Insights

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

The PDF contains numerous links to compromised WordPress sites, suggesting it's part of a link farm designed to lead users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware delivery. No scripts were extracted, but the embedded URLs and heuristic firings point to a common pattern of using compromised sites to host malicious files or redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 7

  • 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 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.
  • 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
  • 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://synerhu.ru/uplcv?utm_term=some+logical+questions+with+answers PDF link annotation
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/160952dd79273c---35821403202.pdfIn PDF document text
    • https://www.alertgy.com/wp-content/plugins/super-forms/uploads/php/files/0d12b7eee6fbb09e85edda6065060b89/69282837714.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/533c373604690ddbd49e0b32766977ef/pemavamobafakifobaf.pdfIn PDF document text
    • http://southportrubbish.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c4e10771f35---kizagomomosexulef.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/qaf4ljd3qh9a4b08q0d8u5nv2f/32313045605.pdfIn PDF document text
    • https://elmaga.lt/components/com_mijoshop/opencart/image/data/files/78705950703.pdfIn PDF document text
    • http://speaklifeiamgreatness.com/files/files/88354121472.pdfIn PDF document text
    • http://ipllaser.in/uploads/95085897118.pdfIn PDF document text
    • http://totaleclipsenv.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e882d16abc---89531953752.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088d4e051746---71500415775.pdfIn PDF document text
    • https://www.eziblank.com/wp-content/plugins/super-forms/uploads/php/files/i4tbii32vud1ci8r0fn8gsnl01/fuwamoxetafipezuxetewegu.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/bcatle1bcksuaq4tcndqfhji7r/zukezinekenovirudik.pdfIn PDF document text
    • https://robinio.de/wp-content/plugins/super-forms/uploads/php/files/4t27klf295l0dlpstj29b007kk/19105278803.pdfIn PDF document text
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/a1ec8c1a2e6f101d3eb7d83472c1ab2d/kerupiwebomoxupolebenen.pdfIn PDF document text
    • http://sattamatkapatti.com/userfiles/file/60016842336.pdfIn PDF document text
    • https://balance-global.com/wp-content/plugins/super-forms/uploads/php/files/rea884cd462jf9fofa9f6b16ed/17573686271.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079687b3b675---donedigabigesaz.pdfIn PDF document text
    • https://alkhairi.co.uk/wp-content/plugins/super-forms/uploads/php/files/4ecf6c5365c11ac1a30e0c05ee0bb6a7/79986205559.pdfIn PDF document text
    • http://fornacedelia.it/userfiles/files/lasoji.pdfIn PDF document text
    • https://trsbarriersdirect.com/wp-content/plugins/super-forms/uploads/php/files/467n2b4o4t07negd7rm0lquhu1/pevuwitilirol.pdfIn PDF document text
    • https://stiff.pl/ckfinder/userfiles/files/87689071736.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ecde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECDE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000104f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104F5 11084 bytes
SHA-256: 0cf494d0e9019d8a2d6512be15bfac38797527f38014fc6a524def3527c18fea
font_02_sfnt_off00011e52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E52 17984 bytes
SHA-256: 81760b23b04578fcd0ffa0b28cf3d91a4313a22c11f448ba561208fec40542ab

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