Malicious PDF — malware analysis report

Static analysis result for SHA-256 3da86d6a865881f4…

MALICIOUS

PDF

72.5 KB Created: 2021-09-25 21:04:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9afb44c7ea1c2062cf79e909c2e88b85 SHA-1: f5553f662f19d5a4ae626de116821325957eeb93 SHA-256: 3da86d6a865881f4cfa6aee76885f449f1d5320652daf9ce941b20eef25d027b
156 Risk Score

Malware Insights

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

The sample is a PDF document identified as a phishing trojan by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs that point to potentially compromised websites or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • 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.
  • 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://boki.hu/editor_up/92009547538.pdf
    • https://infotechloyalty.com/bot/ckfinder/uf/files/57465027335.pdf
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/dfe35i06q5k37on3up735j0tu1/12356125018.pdf
    • http://www.saraviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/161444ab946cbe---bevujusedoxufivikasodano.pdf
    • http://posicert.com/upload_fck/file/2021-9-20/20210920214849305619.pdf
    • http://www.onlinenieuwsbriefversturen.nl/gebruikers/afbeeldingen/zejalivujifoxudite.pdf
    • https://viettincapital.vn/upload/files/5698782104.pdf
    • http://kadh.kr/bobod/upload/file/kivavetepufejeji.pdf
    • http://studioghittigargnano.com/userfiles/files/14746078450.pdf
    • http://chothuexeninhbinh.net/data/dulieu/files/24915317139.pdf
    • http://www.badischer-kunstverein.de/ckfinder/userfiles/files/74274587534.pdf
    • http://wamer.org/userfiles/file/80092581806.pdf
    • http://drprdesaihospital.com/uploads/44075547561.pdf
    • http://dulichtantai.com/files/uploaded/files/56468670162.pdf
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/16148a64d8b673---duvikol.pdf
    • http://trineckevzdelavani.cz/webpagebuilder/ckfinder/userfiles/files/xupelizuxifep.pdf
    • http://elitsatodorova.com/uploadfiles/file/63052316927.pdf
    • http://cupta.org/userfiles/files/20210909110410.pdf
    • https://hfbee.tw/upload/ckfinder_temp/files/20210923152445.pdf
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/c3800c8a4795211da225c4db096849d9/56035091081.pdf
    • http://protok.pro/upload/files/33005592494.pdf
    • http://hodinovysoused.cz/upload/file/97275286062.pdf
    • http://miet-boot.ch/images/uploadedimages/file/60207611714.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=pixlab+photo+editor
    • 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_off0000b8a6.bin
3a228de463ad3791a211f95f1ff004f310e3493edac58a1d7f84b09c334a0020
pdf-font-stream PDF embedded font (sfnt) at offset 0xB8A6 10460 bytes
font_01_sfnt_off0000d03e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD03E 16792 bytes
font_02_sfnt_off0000e850.bin
3c7b7d9fffb761cd4992e7216a748b06741b2b6552c6e20d4b19799a75c31c92
pdf-font-stream PDF embedded font (sfnt) at offset 0xE850 17408 bytes