Malicious PDF — malware analysis report

Static analysis result for SHA-256 b81f776ad885fd13…

MALICIOUS

PDF

84.1 KB Created: 2021-09-02 04:15:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-23
MD5: 544f330c76dc501b53aeed9c18aea601 SHA-1: 954ba49e895350e6d6a7c8a83466556b403b6eea SHA-256: b81f776ad885fd13256731cd53278bb4d9b1b7727411875a40edfa5e11b23045
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by ClamAV and an ML classifier. It uses a callback-phone (TOAD) lure. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://philabc.ru/uplcv?utm_term=fornication+under+control+of+the+king PDF link annotation
    • https://trieurodata.ro/images/file/rapefipudomuronawok.pdfIn PDF document text
    • https://daiichigroup.net/uploads/news_file/67116571606.pdfIn PDF document text
    • http://a-swiss.com/upload/userfiles/file/40488946358.pdfIn PDF document text
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/u2k846vn3g77jvegn8cnp01tso/93959715526.pdfIn PDF document text
    • https://www.paseppe.gr/ckfinder/userfiles/files/palibegiwetaleludonipu.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/1607478961ddd4---87428865783.pdfIn PDF document text
    • http://www.tsssport.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8541bf0049---29489269579.pdfIn PDF document text
    • http://downtowncincyhotels.com/core_degree/admin/images/cms_imagesfiles/36538600957.pdfIn PDF document text
    • http://leap-egypt.com/wp-content/plugins/formcraft/file-upload/server/content/files/160944c3e70720---safinevifagujozik.pdfIn PDF document text
    • https://fallsplat.se/bildbank/file/matipujomekako.pdfIn PDF document text
    • https://www.dolphinrfid.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b487f07071c---37131709995.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac101193ae4---96968123677.pdfIn PDF document text
    • https://www.americansummercamps.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d964170ad5---burase.pdfIn PDF document text
    • https://divanich96.ru/admin/ckfinder/userfiles/files/zepakozepamasefefoxaxo.pdfIn PDF document text
    • http://calisnt.com/uploads/files/fejefavegowagovenopu.pdfIn PDF document text
    • https://projetounificado.com/uploads/files/63511365032.pdfIn PDF document text
    • http://amctop.com/board_data/editor_img/file/202105121006.pdfIn PDF document text
    • https://www.aserspa.net/wp-content/plugins/super-forms/uploads/php/files/h7ohb812kgklqa6spdnfklrup8/leroxiduf.pdfIn PDF document text
    • https://dutchfansitenetwork.nl/ckfinder/userfiles/files/dusamelude.pdfIn PDF document text
    • http://amexeuro.com/an3_Uploads/file/87617052935.pdfIn PDF document text
    • http://the-bom.kr/upfile/files/44861766237.pdfIn PDF document text
    • http://topas.lt/userfiles/file/40698290462.pdfIn PDF document text
    • http://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a4b9f19870---32721749863.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_off0000dd7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD7E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f590.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF590 20264 bytes
SHA-256: f19b5b75cae3f8dd228d520307b7c9e4f64bbacf47635e5bdd53d67469708a17
font_02_sfnt_off00012985.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12985 10756 bytes
SHA-256: a2724f56414963120fdf6aba014e7ca0af9b92e47875410bd1f3d25218fa6c02