Malicious PDF — malware analysis report

Static analysis result for SHA-256 753736a105a4740c…

MALICIOUS

PDF

72.4 KB Created: 2021-04-24 14:44:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: e2f3f75fe4823f574d193072ad242104 SHA-1: 28a333ca28ae539d8a6c884d17a3643482202f0e SHA-256: 753736a105a4740cc91cfe6d88c6006fddf17b1013d4b5ea04af86670dd4b0a1
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to disposable domains and are structured as link farms, a common tactic for phishing or redirecting users to malicious sites. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically identified as a phishing trojan. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, suggesting it was programmatically generated to host these links.

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 https://www.a1touchsolution.nl/sites/default/files/kobovigub.pdf In PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/56489371510.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/65000750087.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/19026354442.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/fezijorimofilafomifum.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/54194604641.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/fadubapep.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/mulakipezumaxusilexuvu.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/21030689395.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/ratasivovo.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/28911573484.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/kubuxodadiwozubak.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/74543186253.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/98819861428.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/40110328039.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=the+temple+of+man+wikipediaPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/20850651402.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d1a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1A8 4900 bytes
SHA-256: 1d6df7e1c4a276352bbb4151007471e7e05e8dad162ab9d71289fdf19c4434c5
font_01_sfnt_off0000e23e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE23E 10192 bytes
SHA-256: b0a997307a356f5be9d33e2c1b6a29e854a90ae2d5cb20a305d977c0336d29a1
font_02_sfnt_off000104e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104E9 4324 bytes
SHA-256: 0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333

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