Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9a42ee83c23fb8e…

MALICIOUS

PDF

77.5 KB Created: 2021-07-12 17:26:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 1756f430e5cdb499aabe7e6df2260dfa SHA-1: 70e0a73ea21fdf7f53ff17f56d06b9b56a323e88 SHA-256: f9a42ee83c23fb8e7e95c0b181a0e18294075393c41036445319594439e035b8
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS uploads. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool, suggesting the PDF itself is not meant for direct user consumption but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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 http://robalton.es/Albums/images/file///86156562134.pdf
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cae94764e7---52533890555.pdf
    • http://igabana.com/upfolder/e/files/20210605015127.pdf
    • https://charlesstreetvideo.com/userfiles/file/mukak.pdf
    • http://envigest.cz/upload/file/75536183783.pdf
    • http://kudusde.org/resimler/files/53984787648.pdf
    • https://hoalavender.net/upload/files/zuvejib.pdf
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/j2o8n1pn74kmhis6prok5teio0/vesenof.pdf
    • https://banghenails.com/upload/file/disatibowewumal.pdf
    • https://hunde-katzen.at/soubory/solonixunaken.pdf
    • http://goref.ru/files/file/69585765468.pdf
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c114782d8dd---72669053355.pdf
    • http://adacu.org/userfiles/file/20210624124722.pdf
    • http://tovicetour.com/FileData/ckfinder/files/20210628_A2219D39FF089239.pdf
    • http://sapaethnic.com/webroot/img/files/xudofenuwoso.pdf
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b5314cb510---44984245943.pdf
    • https://hmv.ir/wp-content/plugins/formcraft/file-upload/server/content/files/160a0e5483cb66---53392011068.pdf
    • https://implant-drill.com/userfiles/file/ridepineka.pdf
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/88b65031c245104f848997fc466ee88d/budekewajutijupibatim.pdf
    • http://www.impactit.in/ckfinder/userfiles/files/3559274247.pdf
    • http://africanhairbraidingsalon.com/userfiles/file/33700555260.pdf
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/43b2b83feb7c4477103d0c35ff667058/watug.pdf
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/21478fug9dd746rjvlor46m8e1/rofafopovupikuxima.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=building+restful+web+services+with+go+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_off0000ca9e.bin
3e59c5792a5e18eb429e18408b2c1d37f7009b340ea8538d6b9a85035b4947dd
pdf-font-stream PDF embedded font (sfnt) at offset 0xCA9E 16860 bytes
font_01_sfnt_off0000f6df.bin
6b362102ac6c9e9fc7006b7c78537046fcacf5d848c60c1fe90ca13912ac4224
pdf-font-stream PDF embedded font (sfnt) at offset 0xF6DF 11180 bytes
font_02_sfnt_off0001109b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1109B 16792 bytes