Malicious PDF — malware analysis report

Static analysis result for SHA-256 81cf08923e36b6cf…

MALICIOUS

PDF

87.2 KB Created: 2021-07-06 08:30:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 15e7c0ea73131992eb909d501c07ab09 SHA-1: f342b1d93d88dbf971f03684a3da33f33147df05 SHA-256: 81cf08923e36b6cf6d88b2a0d14a976b1adab012658a173d97c286f524c92da2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a link farm pointing to multiple compromised WordPress upload directories, suggesting an attempt to host malicious content or redirect users to phishing sites. The presence of numerous unknown URLs further supports this phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://www.asahinadigital.com/wp-content/plugins/super-forms/uploads/php/files/uhsvctnu3l3nqrdugfrh9qevgv/deropuguzefijupunobo.pdf
    • https://donnasalon.ru/wp-content/plugins/super-forms/uploads/php/files/7bd18ac6f1819436cea6f8a4b890dc33/juzawawag.pdf
    • http://ventilatoryzlin.cz/images/file/76404322402.pdf
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/76f12c266e212f635948bf9167f33c6e/kubawa.pdf
    • https://b2b-intelligence.it/uploads/file/mitudogeziseraworedinefu.pdf
    • http://aep-tc.com/cache/fck_files/file/16537867884.pdf
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160945fc2952ab---58593315688.pdf
    • https://eclipsetheaters.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081c4ce7002a---66623689353.pdf
    • http://www.victorian-manor.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1609ef478c4236---65260603422.pdf
    • http://evpltravel.com/xv_image/file/70725443348.pdf
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/skq4qb67sl6fr9iijouqsmf9c8/74323873937.pdf
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7b0c36c0dc---45052367951.pdf
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608f0aaedc375---89472741919.pdf
    • https://esteticarcare.com/wp-content/plugins/super-forms/uploads/php/files/87db2e1aaa6c7a8467352fabb98d8f2d/wowifozelaxisukizeb.pdf
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b824ccca0e---39897760455.pdf
    • https://btegypt.com/file/marilamabizizijelux.pdf
    • http://botosani.ro/img/uploads/file/48161363743.pdf
    • https://messianic.live/wp-content/plugins/super-forms/uploads/php/files/79d36af9063829f754ae6312e61c5266/47046026480.pdf
    • http://saigondome.com/uploads/userfiles/file/41928479352.pdf
    • http://phamtrangia.com/upload/files/wosojofa.pdf
    • http://ctkupavna.ru/upload/file/jakitozepejixosez.pdf
    • http://bjsprt.com/uploadfile/file///2021070602513079.pdf
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e0fa16c2936---81917913711.pdf
    • http://avtoarka.ru/wp-content/plugins/super-forms/uploads/php/files/4fdfbe928b5ff251eca2b1b0ade2b3a3/tijebakoruzi.pdf
    • https://plasy.com/uploads/file/7049163557.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=hot+dogs+on+stove+top
    • 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_off0000f515.bin
cd9c80cb29b03d834b34e799e129f91bb18c04b2b954fe21060925fb3d9ddb93
pdf-font-stream PDF embedded font (sfnt) at offset 0xF515 16768 bytes
font_01_sfnt_off00012095.bin
4e517a6707ab4f7ef1a97593596504a0a4f9aed3e899267c3d26ecc0aaf0dcbb
pdf-font-stream PDF embedded font (sfnt) at offset 0x12095 10224 bytes
font_02_sfnt_off00013766.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13766 16792 bytes