Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1135d73007cdece…

MALICIOUS

PDF

75.7 KB Created: 2021-09-02 05:09:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 812bce5edad52a7951770ea7d7d870c5 SHA-1: 477f154316f7b9644ba9aac595b523d164446121 SHA-256: b1135d73007cdecec08db7147edb0f0ea4dfdecd8d1791ee6aa088810271d140
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm or phishing lure. The presence of embedded URLs and the PDF structure strongly suggest it is used as a delivery mechanism, likely for a second-stage payload, aligning with spearphishing attachment tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://smidgel.ru/uplcv?utm_term=centralisation+meaning+in+telugu PDF link annotation
    • https://oilbasaro.com/web/images/ckfinder/files/20210720171034.pdfIn PDF document text
    • https://nnt52.ru/userfiles/file/40044808460.pdfIn PDF document text
    • http://alpanelektrik.com/depo/sayfaresim/file/nipowabifux.pdfIn PDF document text
    • https://aptitudeclass.com/ckfinder/userfiles/files/zatiba.pdfIn PDF document text
    • https://razvozka24.ru/wp-content/plugins/super-forms/uploads/php/files/af3306dc386bf4a13ffcd799fc3c8a21/zilabazodibalunesaju.pdfIn PDF document text
    • https://www.ftha.org/admin/ckfinder/userfiles/files/bawibiji.pdfIn PDF document text
    • http://www.cargeacrew.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a067e849d12---69031245398.pdfIn PDF document text
    • http://www.wallisandemmanuel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e92c1248dc6---54772386051.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160bc54a2b0932---32744064260.pdfIn PDF document text
    • http://mega.kz/media/upload/files/rojasepiwumoza.pdfIn PDF document text
    • http://cuacongtrinh.vn/upload/files/79254034943.pdfIn PDF document text
    • http://parquessolaresdenavarra.com/userfiles/files/barel.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/160a5ba9b57174---44432562222.pdfIn PDF document text
    • http://witnesstherealist.com/wp-content/plugins/super-forms/uploads/php/files/1dae5313ef7084cbb7ccd750fac14c0c/93782568484.pdfIn PDF document text
    • https://pasifikendustriyel.com/userfiles/file/dojijenu.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a18bc3cec33---pibesazelokusofuduvexasi.pdfIn PDF document text
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1612c83eb58831---poburakunobofeduze.pdfIn PDF document text
    • http://tokyoracing.hu/userfiles/file/25855202091.pdfIn PDF document text
    • http://women-for-marriage.com/ckfinder/userfiles/files/16544513719.pdfIn PDF document text
    • https://tirthmobile.com/wp-content/plugins/super-forms/uploads/php/files/153gjh0r4gcogimtis4mb6nk51/43686912862.pdfIn PDF document text
    • https://feng-shuiworld.com/userfiles/file/peninuba.pdfIn PDF document text
    • https://gestcargo.com/uploadfiles/file/64245986663.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a415b24a67f---2234111362.pdfIn PDF document text
    • 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_off0000c321.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC321 17776 bytes
SHA-256: b64a7eba2aba35f4cb10b7440e2980f9d9a62a17b1bf68c1bcbafc03dc8dcc20
font_01_sfnt_off0000f0a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0A7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000108be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108BE 10580 bytes
SHA-256: 06e18cb2740f889ec00de936192bac79e8145ddffbe29aa863a3b874046c0af4

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