Malicious PDF — malware analysis report

Static analysis result for SHA-256 99d6e7a4aa19e5fa…

MALICIOUS

PDF

114.7 KB Created: 2021-09-05 19:38:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 73ba0867b7706ac8fe9b03ca7c35741d SHA-1: e53c5aa3f96d9d9519e593f27d78cb2269c39a0a SHA-256: 99d6e7a4aa19e5fa74b1416eab1e07279222677487489915f7bf6f812293ae0b
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, forming a link farm. Heuristics indicate this is a fake invoice or payment lure, and a callback phishing pretext, suggesting the user is meant to click a link to resolve a supposed issue. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to download a second-stage payload via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

Heuristics 8

  • 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://crewmak.ru/uplcv?utm_term=plan+comptable+pdf+syscoa
    • http://ahxxzx.com/userfiles/202105/file/pizafi.pdf
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607259fdb2a5f---8640090657.pdf
    • https://247hvac.ca/fabulous1/uploads/files/87636340267.pdf
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/1611d8fd07d93c---7893694797.pdf
    • http://aqbnb.com/uploadfile/file/poluvipatav.pdf
    • http://kreativitaet-stadlhofer.at/global/images/userfiles/file/12256185565.pdf
    • https://stpetejazz.com/wp-content/plugins/super-forms/uploads/php/files/tpe7v0r5hm6m28g9v18v02hm8h/81263764070.pdf
    • https://www.frankreich-ferien.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a9d10dc467b---bubenumexavekotetapa.pdf
    • http://le-bouquet.be/userfiles/files/36629978924.pdf
    • https://aadharshilaschool.org/userfiles/file/siraxilonojamejine.pdf
    • https://sg-design.top/wp-content/plugins/super-forms/uploads/php/files/dd958206f27cb859c616b3e8c711e4e3/mawiwixaneduj.pdf
    • http://guides2alpes.org/uploads/file/duxufarufumeneromigekekot.pdf
    • http://svs-pm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077ebefd6081---62233527644.pdf
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608ba867d07fd---87286930668.pdf
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/hv9a41797dv3vfaqi6hmiehgq5/38583591180.pdf
    • https://majubesar.org/contents/files/tesafejoximakamutosamul.pdf
    • https://moolans.com/uploads/files/mibaf.pdf
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/60c62fc3f2ba19d53712b10e8a9d026d/72680790726.pdf
    • https://gertiesbloomers.com/kousumi/nulook/upload/fckimages/file/kanaw.pdf
    • https://doktor-ara.com/userfiles/files/99105343964.pdf
    • http://brighterhealthcare.co.uk/wp-content/plugins/super-forms/uploads/php/files/5l017msjv2kvs2q2ihedsd9qmf/2203079801.pdf
    • http://rolmech-strzelno.pl/Upload/file/lovosim.pdf
    • https://bamfieldrental.com/userfiles/file/jotenekumemukim.pdf
    • https://teenvolunteer.org/wp-content/plugins/super-forms/uploads/php/files/1b683a1e86a10703daf90a6bc1e88eeb/78452335160.pdf
    • http://imhkayseri.com/resimler/files/xumepabujobixominusewol.pdf
    • 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_off0001593a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1593A 16792 bytes
font_01_sfnt_off0001714c.bin
448868dd62184c35e83d6262c0ac1a2412956e37bd745f4fd7d7b551bf704bf9
pdf-font-stream PDF embedded font (sfnt) at offset 0x1714C 19628 bytes
font_02_sfnt_off0001a3ce.bin
e8c3c057fd1ce8449bba570f97162d1613641411dbabe84f3e6a87a7b3dd30d2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1A3CE 10844 bytes