Malicious PDF — malware analysis report

Static analysis result for SHA-256 573d7a636bb5e473…

MALICIOUS

PDF

82.1 KB Created: 2021-09-11 13:48:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 032766e12af523523f65cf665c954892 SHA-1: 5c05379369c777ab1d51cb4be48b31b2d786843f SHA-256: 573d7a636bb5e473db0daf166978b2a6d2ab604e0ae99b155ba521d285c11171
176 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. The document body is unreadable, but heuristics indicate it functions as a link farm and a callback phishing lure, prompting users to call a phone number under the guise of a billing or security issue. While no scripts were directly extracted, the presence of embedded URLs and the nature of the heuristics suggest potential exploitation or redirection to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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) 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 http://www.yeosung21.or.kr/ckfinder/userfiles/files/1631082731.pdf In PDF document text
    • http://abwalabamaave.com/uploads/files/72516043970.pdfIn PDF document text
    • http://jingyilin.org/uploads/file/kedodudegezolomanexon.pdfIn PDF document text
    • https://sunarchegypt.com/userfiles/file/54482138981.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///15099005018.pdfIn PDF document text
    • http://ifa-astrologie.de/userfiles/file/64953998749.pdfIn PDF document text
    • http://pobierzplik.pl/uploads/files/76860478535.pdfIn PDF document text
    • http://kleni.cz/userfiles/file/13526040592.pdfIn PDF document text
    • http://sofia-es.tokyo/yamituki-n/uploads/files/malepedapoganesibisojefu.pdfIn PDF document text
    • http://axwelindia.com/uploads/67918612029.pdfIn PDF document text
    • http://www.ktgroup.co.uk/ckfinder/userfiles/files/xabenuwurolibamosurila.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/094fcd9819cc8a0f9c949020fff477b6/92859897942.pdfIn PDF document text
    • https://stmpallet.com/ckfinder/userfiles/files/28645939761.pdfIn PDF document text
    • http://webinaris.net/ckfinder/userfiles/publics/files/ziniwaxivanuxowajizekulow.pdfIn PDF document text
    • https://tideandtigers.com/ckfinder/userfiles/files/58638809238.pdfIn PDF document text
    • http://anshan56.cn/userfiles/file/1631346526935412047.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613631f26ef48---62865550627.pdfIn PDF document text
    • http://www.me.ntou.edu.tw/ckfinder/userfiles/files/20210911_095727.pdfIn PDF document text
    • https://www.growxponential.com/wp-content/plugins/super-forms/uploads/php/files/1lr19kabsec2usd61tea0l32as/41085687836.pdfIn PDF document text
    • https://uzsienis.cvzona.lt/resources/img/files/26608288861.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/rpb8ar1ee7k279f5bjsiq942hr/5170073134.pdfIn PDF document text
    • http://staceyasp.com/UserFiles/file/92381958817.pdfIn PDF document text
    • http://tehpromyar.ru/media/file/41818987555.pdfIn PDF document text
    • http://xyr59.com/filespath/files/20210905094250.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=instagram+see+private+postsPDF 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_off0000db9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB9D 10564 bytes
SHA-256: 8a50c03f469efb1e8c60ddc1c77b1f9db8349d18d1f8c529259342b6604f6018
font_01_sfnt_off0000f3b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3B7 17920 bytes
SHA-256: 6810acd21aca98da89de28f450f560892693645648f484e932974b6dc2689448
font_02_sfnt_off000121bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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