Malicious PDF — malware analysis report

Static analysis result for SHA-256 ace479910674ef9e…

MALICIOUS

PDF

84.9 KB Created: 2021-08-24 22:44:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 3909c53fc0a8fe3fe05b8c95a0e36328 SHA-1: ea13349a358c9222f6bbbb739944a2c24576ed23 SHA-256: ace479910674ef9eb940367bf60785252aabda4e98d5bc46ad9dc14a19d46989
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous URLs, many of which point to compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://elcoengineeringco.com/userfiles/file/20709422498.pdf In PDF document text
    • https://aeap.com.br/ckfinder/userfiles/files/77783184945.pdfIn PDF document text
    • http://studioassociatoemc.com/userfiles/files/pogejefikawuga.pdfIn PDF document text
    • http://fcv-bo.org/data/fcv-bo/userfiles/file/39461353761.pdfIn PDF document text
    • http://rayocazar.com/images/elfinder-1.1/files/file/mivunovebig.pdfIn PDF document text
    • https://thejasmineway.net/wp-content/plugins/super-forms/uploads/php/files/k1oqum41rn6545b1vk14rhgci7/90397211960.pdfIn PDF document text
    • http://www.associatedomains.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608134e8bbed6---8413450101.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f9617bd714e---fibasemudinupab.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/al63q4j03sdjoinabo1jjai008/23469291441.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b05763780e5---rexuximolax.pdfIn PDF document text
    • http://easternhoteljeju.com/FileData/ckfinder/files/20210629_D71C2D91EA1D4EFD.pdfIn PDF document text
    • http://visit-pune.com/userfiles/file/9670634419.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab77ab1361b---43421068188.pdfIn PDF document text
    • https://revapackers.com/wp-content/plugins/super-forms/uploads/php/files/763hcods0gnjn65601vikduruq/7892514828.pdfIn PDF document text
    • http://www.lightingandhvacexpo.com/wp-content/plugins/super-forms/uploads/php/files/3dd0b4d6336ca2b53920fb385e459aa1/59883036597.pdfIn PDF document text
    • http://www.franklinwebdesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160865dca9eab3---86027762865.pdfIn PDF document text
    • http://sys-svinding.dk/userfiles/file/vutexukalumodeji.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071b39b40e67---zumojakopa.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/8131a84ca9690935d626bc8d718821b3/doporogikuxasuvo.pdfIn PDF document text
    • https://tese.in/ckfinder/userfiles/files/93673558587.pdfIn PDF document text
    • https://kalyna.ua/sites/default/files/userfiles/file/39344686265.pdfIn PDF document text
    • http://ecole.ru/text/images/file/97301817491.pdfIn PDF document text
    • http://sl1971.com/clients/5/51/517263f0417f9379c67e6eba0e0bdfe8/File/kobupow.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=the+number+of+species+living+within+an+ecosystemPDF 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_off0000e198.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE198 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f9af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9AF 11396 bytes
SHA-256: f5122bc8e8ff324c05ef4c4d495b2df89efc45e8118404609acfad07b3f39df8
font_02_sfnt_off0001143a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1143A 18376 bytes
SHA-256: 9178c0439f6503f3b449085dae9fe9e8b8857b87b2b8289a11fa7a7ad09a87f3