Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b852de2879a2cc5…

MALICIOUS

PDF

81.4 KB Created: 2021-08-17 08:46:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 28a1765e755192b6e6bade974544f324 SHA-1: 3d5f3fc44d22aac71ca5d5aab08c3172700df5e2 SHA-256: 5b852de2879a2cc5e15cbef46a0a9df8e9001947ab583a29922cd36e8f414e63
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating it is likely a phishing or trojan delivery mechanism. The presence of numerous URLs, many hosted on compromised CMS uploads or disposable hosting, suggests a link farm designed to redirect users to malicious content or download further payloads. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://queure.ru/uplcv?utm_term=how+many+types+of+infinitives+are+there+in+spanish
    • http://theclubburger.com/uploads/files/modusuxe.pdf
    • http://jfe.hk/userfiles/kozoze.pdf
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16075b87253c20---panomuzejavovizapi.pdf
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/af6e2bdd26c4ab5aa03bc30941044b6d/82199362257.pdf
    • https://jetzterstrecht.hamburg/wp-content/plugins/super-forms/uploads/php/files/fle9vobm0d2tig565unmfdfpk5/82361380961.pdf
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607252d012cf8---48534584059.pdf
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a0f1a50351---33970634550.pdf
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/161082684ce888---77895711282.pdf
    • http://www.gamylai.vn/uploads/files/jativefif.pdf
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b488a4adc5---zeveze.pdf
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e975506f9cc---nexafelize.pdf
    • https://nic-irq.com/userfiles/files/66185432214.pdf
    • http://dodici12.ru/wp-content/plugins/super-forms/uploads/php/files/on9aue6esa3tfp8u38rj8jcr66/27803807671.pdf
    • https://spheresignal.com/app/webroot/userfiles/files/86629963805.pdf
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/39415284984ef6f210e5034b3fa86981/57937788302.pdf
    • https://walkandsmile.com/userfiles/file/41179485355.pdf
    • http://thepnguyentran.vn/media/ftp/file/fisoxetawuziluvorilamoka.pdf
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/160850bfdb422a---89010973956.pdf
    • http://ngpsusa.com/wp-content/plugins/super-forms/uploads/php/files/f39vvvnvaqjd6p5bthqo3ha71h/lugixeli.pdf
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/ad3ookq8kntgb1ovarhjd5pik5/kuboxitagopiju.pdf
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/160734bda6b8bb---pokosojawulojasasaneririv.pdf
    • http://lab4050.com/upload/editor/file/21514562154.pdf
    • https://aimtronu.org/userfiles/file/37563211791.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608c2beb83ca5---vasadituzuzibu.pdf
    • https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae3b84ee3af---gurebujimupejulateneda.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_off0000dc44.bin
334d6764db9501e6d8e408981f1e5d7a8c4390cb160d439fcb70611543259a7a
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC44 16900 bytes
font_01_sfnt_off00010754.bin
72a19cb1ed1c4bdf57e39022f6e583c7c26d232ed412266e78d4e74aecf3a7a0
pdf-font-stream PDF embedded font (sfnt) at offset 0x10754 10836 bytes
font_02_sfnt_off00012035.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12035 16792 bytes