Malicious PDF — malware analysis report

Static analysis result for SHA-256 93b93cfd090b4cae…

MALICIOUS

PDF

87.2 KB Created: 2021-09-08 03:05:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: fb0596a42756ae287688dafd00b09a1c SHA-1: bda681217aa282f343f6339b8e99d42964aa1309 SHA-256: 93b93cfd090b4caeebb9f0acc828556754264943646fb1e80fe21d7a84ec0513
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous embedded URLs that form a link farm, pointing to compromised websites and disposable hosting, suggesting an attempt to distribute phishing content or malware. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 https://chcial.ru/uplcv?utm_term=addition+subtraction+worksheet+for+grade+3 PDF link annotation
    • http://www.salac.cz/ckfinder/userfiles/files/55408323201.pdfIn PDF document text
    • https://www.phuketvillarentalandservices.com/ckfinder/userfiles/files/13165529742.pdfIn PDF document text
    • http://liyangah.com/Upload/file/jizidipogunipevaku.pdfIn PDF document text
    • https://copab.tn/216mag.svn/uploads/files/xulupavivojisise.pdfIn PDF document text
    • http://ckpak.com/fckeditor/userfiles/file/xulurupok.pdfIn PDF document text
    • http://automsystem.com/UploadFile/file/20210502210604226.pdfIn PDF document text
    • https://loan-financial.com/wp-content/plugins/super-forms/uploads/php/files/00279e806ae09b913e7679ae2bddfd61/75038627137.pdfIn PDF document text
    • http://diagonal.org.ar/wp-content/plugins/formcraft/file-upload/server/content/files/16098e7b8396a9---98217889567.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/07b0910869a1bd9108eacd64e13fc1a2/4136295495.pdfIn PDF document text
    • http://nprofit.hk/userfiles/22211746128.pdfIn PDF document text
    • http://industrialdevices.in/uploads/timave.pdfIn PDF document text
    • http://woodwork.pl/ubezpiecz/obrazy/file/40315819676.pdfIn PDF document text
    • http://chataphan.com/file_media/file_image/file/worinoxubevofakavodezev.pdfIn PDF document text
    • https://mclandpin.com/calisma2/files/uploads/mebebenumotamir.pdfIn PDF document text
    • http://timebymtm.com/upload/files/63002129713.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa3a728993f---4975557332.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612a86a1b0a1d---mekanilo.pdfIn PDF document text
    • http://www.jimenez-casquet.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f7d7ac62cc7---95498730260.pdfIn PDF document text
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/buposemirisupusuja.pdfIn PDF document text
    • https://www.kalirich.com/wp-content/plugins/super-forms/uploads/php/files/fjj56utm0fk5l3uc14neip8d92/55844810102.pdfIn PDF document text
    • https://bangprice.combangprice.com/beta/cms_image/file/66206185323.pdfIn PDF document text
    • http://soc-in.com/data/media/files/72499833501.pdfIn PDF document text
    • http://innovatepc.com/userfiles/file/1509697375.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_off0000efb1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000107c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107C3 17204 bytes
SHA-256: 83930eb607670a4970d4c04544501460cbb41843599b19b311c6c08eb349dccd
font_02_sfnt_off0001346b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1346B 11280 bytes
SHA-256: 5a1b6f00f2b2eb4f804d32425aadfcaf478b30f4b187e56b715746bff6cb8404