Malicious PDF — malware analysis report

Static analysis result for SHA-256 528cb77e708209e3…

MALICIOUS

PDF

79.8 KB Created: 2021-09-17 03:55:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 124158d4945910ce50ba4eba486779ff SHA-1: ca7a3da5cbab0bb73c91f51bf19c1ee1b99aec44 SHA-256: 528cb77e708209e3bebaef8f92f3fe6bdc8c6e0fbf1b5aad3f3581c5eb28244d
206 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external PDFs hosted on various domains, some of which are IP-based, suggesting a link farm designed to host malicious content. The 'SE_CALLBACK_LURE' heuristic indicates the document likely attempts to trick users into calling a fake support number, a common phishing tactic. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to deliver a second-stage payload via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 8

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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 https://chcial.ru/uplcv?utm_term=how+to+change+your+email+name+on+android PDF link annotation
    • http://mebel-moscow.com/content/xuploadimages/file/woxajasixinetogutuji.pdfIn PDF document text
    • http://orgue-chantepie.info/FCKeditor/upload/file/dirifu.pdfIn PDF document text
    • http://amindoost.ir/images/upload/files/39122667040.pdfIn PDF document text
    • https://egca.fr/userfiles/file/77619132138.pdfIn PDF document text
    • https://nnkcreations.com/userfiles/file/46031272244.pdfIn PDF document text
    • https://tnmkor.com/FileData/ckfinder/files/20210908_66018E2605FB2F1D.pdfIn PDF document text
    • http://iktoktatas.hu/files/file/50411822494.pdfIn PDF document text
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f1bc0c6320---73490465090.pdfIn PDF document text
    • http://halaljones.com/uploads/files/lusopinopove.pdfIn PDF document text
    • http://akvatoria.by/UserFiles/files/vuniwekigekajavigogala.pdfIn PDF document text
    • https://www.moxiclear.com.au/application/third_party/ckfinder/userfiles/files/19379567904.pdfIn PDF document text
    • http://spbmedax.ru/sites/default/files/uploads/zuzejorafuxidivobebane.pdfIn PDF document text
    • http://ambulatorioveterinarioilghirlandaio.it/userfiles/files/danepatarawedopi.pdfIn PDF document text
    • http://moskvaznaet.ru/upload/files/22693223559.pdfIn PDF document text
    • https://samsungdvm.net/upload/ckfinder/files/10013106311.pdfIn PDF document text
    • http://www.udelimpa.es/ckfinder/userfiles/files/xegoginubinus.pdfIn PDF document text
    • http://3qlohas.com/CKEdit/upload/files/kaxemujefajetepubinovus.pdfIn PDF document text
    • http://mybyblos.com/userfiles/file/runanodimagosoxaja.pdfIn PDF document text
    • http://www.awakohchang.com/image/upload/File/ifakexatirires.pdfIn PDF document text
    • https://vestol.bg/files/file/23280378592.pdfIn PDF document text
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/9a173136ff522559da72581aa5bfc336/43187049344.pdfIn PDF document text
    • http://140.121.161.111/ckfinder/userfiles/files/dumibavigunadivuzewotob.pdfPDF 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_off0000d278.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD278 17664 bytes
SHA-256: 9a261f0ec084254ee1941c39dca401334e171212ad8eaf058f143fbcfc1e1b58
font_01_sfnt_off00010003.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10003 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001181a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1181A 10940 bytes
SHA-256: 20a4abcf8f3c0316f06de00d18d41decb07feebe093989fbd1bf8466ac2ae979

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