Malicious PDF — malware analysis report

Static analysis result for SHA-256 50863d4b27a124a0…

MALICIOUS

PDF

81.1 KB Created: 2021-09-20 00:03:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a8c8c8be97b3abb0a9531f5424bda0f1 SHA-1: a01fefe9438bcbe1777841c91eb85e94d97bd8bf SHA-256: 50863d4b27a124a0fb1f1ef10304ab969ed1b62d490f18c37334a22e2ecc1a09
176 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple unknown domains, a common tactic for phishing or SEO poisoning. The ClamAV detection and ML classifier strongly indicate malicious intent. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the presence of numerous external links is the primary indicator of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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 http://unseretochter.ch/images/file/niberireliminosul.pdf
    • http://phuocthuan.vn/images/pic/file/tuwejokaterufimivuzod.pdf
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ce771c1fc3---sezinu.pdf
    • http://usairsprings.com/userfiles/file/63310186399.pdf
    • http://niszczeniewaw.pl/userfiles/file/23288645357.pdf
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/5c8053adb8ad90381016b895b597f3cd/62545346912.pdf
    • http://tulga.ru/editor/files/biwinimotilakutokek.pdf
    • https://takarasushimn.com/userfiles/files/vanarupeliviziwusuvipi.pdf
    • http://medicaldistri.com/ckfinder_files/files/90532679839.pdf
    • https://alkhairi.co.uk/wp-content/plugins/super-forms/uploads/php/files/d2e6bc5eb6c2fd7b25fb50e2f5348ea1/dunorogewuvigu.pdf
    • http://3e3i.com/UserFiles/file///52865498579.pdf
    • http://abnicum.ru/files/file/sowexofexuniwojag.pdf
    • http://www.awakohchang.com/image/upload/File/ujafudevarez.pdf
    • http://www.zywawiara.pl/pliki/nafazewibelifuxu.pdf
    • http://oembag.com/uploads/files/202109132052406246.pdf
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1613276ae86f3c---woguben.pdf
    • https://inprovitperu.com/ckfinder/userfiles/files/batanemopasepizogovivomal.pdf
    • http://agcslohian.com/userfiles/file/lulujot.pdf
    • http://sor1310.com/userfiles/file/44465847812.pdf
    • http://carbontuning.ru/file/43235396384.pdf
    • http://luckysim.com/userfiles/file/18649253576.pdf
    • http://anton-joyeros.shopcloud.es/ckfinder/userfiles/files/77252725531.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=opera+mini+to+download+for+android
    • 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_off0000d7c5.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD7C5 16792 bytes
font_01_sfnt_off0000efdc.bin
92f193a685d0a00f318c760b8a4dbcc9a93dc37d0f45257e0a0345b2f299b163
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFDC 10604 bytes
font_02_sfnt_off00010814.bin
b20c6077d9c8e75b251b3ec9b018717a2eb96b9cbde8f381869ad60bc2f7b0ca
pdf-font-stream PDF embedded font (sfnt) at offset 0x10814 18108 bytes