Malicious PDF — malware analysis report

Static analysis result for SHA-256 91e8b1fe1fb47d0a…

MALICIOUS

PDF

78.2 KB Created: 2021-09-13 11:20:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: cc4467c9a84d591e508a361f542a91aa SHA-1: 0468a0fc351055b98a728591d01e61ed8b01e18c SHA-256: 91e8b1fe1fb47d0a18561cdf1bfbbc7cfc2c93bc8fe137640758fc46ea001f63
176 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating a malformed exploit stream and a link farm pointing to compromised WordPress upload storage. The document body is unreadable, but the presence of numerous external URIs, many hosted on disposable domains or compromised sites, strongly suggests a phishing or malware distribution attempt. The primary IOCs are the URLs hosted on compromised or suspicious domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ea1152e0a1---legakepobuza.pdf In PDF document text
    • https://foundryindia.org/userfiles/file/fuvejupu.pdfIn PDF document text
    • http://prosefkuchare.cz/userfiles/vidoluzepoxexaganifa.pdfIn PDF document text
    • http://gevenschoenen.nl/ckfinder/userfiles/files/sorab.pdfIn PDF document text
    • https://akonis.ch/userfiles/files/siwasosud.pdfIn PDF document text
    • https://manpowernepal.net/ckfinder/userfiles/files/2152757078.pdfIn PDF document text
    • http://sangiorgioautoservizi.com/userfiles/files/nigonijosowozoxokado.pdfIn PDF document text
    • https://cfbadalona.net/ckdata/files/vavomilov.pdfIn PDF document text
    • https://digireg.nu/upload/26953114819.pdfIn PDF document text
    • https://www.sexualaufklaerung-schule.ch/ck/ckfinder/userfiles/files/30624744488.pdfIn PDF document text
    • http://ranahytta.com/ckfinder/userfiles/files/fobimisuxi.pdfIn PDF document text
    • https://hiroyoung.com/data/files/vowebiboxovukexa.pdfIn PDF document text
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/161343642ee5b0---52123368006.pdfIn PDF document text
    • https://carrieres-pierre.com/userfiles/file/10003653262.pdfIn PDF document text
    • https://sskundal.com/userfiles/file/pasatatekimezeku.pdfIn PDF document text
    • http://kalmi.ru/upfiles/files/rolowi.pdfIn PDF document text
    • https://tocgia247.com/wp-content/plugins/super-forms/uploads/php/files/gon092hgmkt5df0umied3qlbja/sojutax.pdfIn PDF document text
    • https://heuresromantiques.com/upload/files/nuragixegudopusemetid.pdfIn PDF document text
    • http://salt17.com/userfiles/files/46314471773.pdfIn PDF document text
    • http://icaalliance.org/filespath/files/20210906183304.pdfIn PDF document text
    • https://mangalargalux.com.br/ckfinder/userfiles/files/72273215133.pdfIn PDF document text
    • https://malayalamfoundation.org/admin/my_files/file/61004629263.pdfIn PDF document text
    • http://erodiertechnik-wenzel.de/userfiles/file/xalege.pdfIn PDF document text
    • http://synthecinter.com/userfiles/files/59454190692.pdfIn PDF document text
    • http://tcgardening.com/userfiles/file/2021090207282873499.pdfIn PDF document text
    • https://etevent.itweald.com/uploads/files/613df285991ee.pdfIn PDF document text
    • https://greenways.at/userfiles/file/mekoxo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=sonic+fantasy+xPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c71d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC71D 10340 bytes
SHA-256: fc76173b9a5312cecf67d474cba40974a2a4d717426fea7eddf109c436f1123d
font_01_sfnt_off0000de9e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE9E 19760 bytes
SHA-256: 1f76269bec14c2d3e4520ff0ea626aeef25fa9fdd4654f56da2a2bc566c2e80a
font_02_sfnt_off000112b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112B5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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