Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fd1cecabb1de58…

MALICIOUS

PDF

87.3 KB Created: 2021-06-25 19:30:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 897fce28a9c514a1bc8906025fc53ed5 SHA-1: 35f1fa9801ba70f455a652313bc23e8c96a64907 SHA-256: 81fd1cecabb1de58284d7d6281af2cf5290b1ecff06ba52da267ac884ec7f2ab
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress sites, likely hosting malicious content. The 'SE_CALLBACK_LURE' heuristic suggests the document's content is designed to trick users into calling a phone number, a common tactic in tech-support scams and callback phishing. No scripts were extracted, but the PDF structure and URL patterns are indicative of a phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) or Microsoft license-boilerplate documents that carry no urgency or charge/dispute escalation.
  • 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.nestroots.com/wp-content/plugins/super-forms/uploads/php/files/elvg0dadvr95dqso303g6d0th2/pojajebixawo.pdf In PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607930415b65a---66553828278.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf486594c16---rojefirozar.pdfIn PDF document text
    • https://rfcorporation.net/wp-content/plugins/super-forms/uploads/php/files/cd0488169c5007b07f1d2396d97d5ddb/83055017387.pdfIn PDF document text
    • http://fashionflutters.com/ckfinder/userfiles/files/6387893389.pdfIn PDF document text
    • http://livestreaming.group/wp-content/plugins/super-forms/uploads/php/files/oomljm2hfnhijgc5ijttlqopathsno63/16152341657.pdfIn PDF document text
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/818dbc222dedd405f38332b93a3a029f/13812986272.pdfIn PDF document text
    • http://jagatjyotischool.org/jagatjyotischool/userfiles/file/jizikumat.pdfIn PDF document text
    • https://bluebeakbranding.com/wp-content/plugins/super-forms/uploads/php/files/9456287e6d6d95d2d10dd87db4a6764a/jumetozokubik.pdfIn PDF document text
    • http://dailycan.com/userfiles/files/misitizorusubide.pdfIn PDF document text
    • https://wentworthre.com/wp-content/plugins/super-forms/uploads/php/files/ab16c73652a128adc655e06b4642993c/xixunufemimenomelagiris.pdfIn PDF document text
    • https://whiteelephant.co.in/wp-content/plugins/super-forms/uploads/php/files/1d2fc94a56881d862811f4dda450eb6d/21050480574.pdfIn PDF document text
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be7d0f22c45---16904286745.pdfIn PDF document text
    • http://thehawthornnyc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608fbc33b9652---bokalobededojoleve.pdfIn PDF document text
    • https://mk-sito.it/uploads/file/25504172360.pdfIn PDF document text
    • http://sequirk.ie/userfiles/file/vufapovovijejubano.pdfIn PDF document text
    • http://changecn.net/ckupload/files/zozixenesewujezegifimativ.pdfIn PDF document text
    • https://usssecuritate.ro/userfiles/file/bexonumubuketurovurexamuj.pdfIn PDF document text
    • http://www.peopleoftheheath.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb01bea5622---bapugikazapemutaz.pdfIn PDF document text
    • https://www.picmephotoboothhire.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606e9972324e3---jegetamawigomiwibikito.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=jee+mains+application+form+2021PDF 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_off0000f0f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0F2 10924 bytes
SHA-256: d0ed7bd6e170d3f23916ea1c1e1e564dc24d82d36ebb9e0f318a7fdb3dfe920d
font_01_sfnt_off00010a55.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A55 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012267.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12267 17444 bytes
SHA-256: 583829d48ec2ef6fc4f459894344027826484cdeb0ced5e921b729a3c4ecda7e

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