Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca8bc4d7e0efcde4…

MALICIOUS

PDF

101.4 KB Created: 2021-08-01 15:36:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 92d2563f1deaf00def310e41ade74377 SHA-1: 80db82d2726feaa7612ea5d536a8dadd1135e17b SHA-256: ca8bc4d7e0efcde4f29abfd79a41f425443de57e9c8f5fda89f7a238c70cc4be
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as a malicious PDF by multiple heuristics and a machine learning classifier, with ClamAV detecting it as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm or redirection mechanism. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a tactic to obscure the true destination or leverage compromised infrastructure. While no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with phishing or malware delivery attempts.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9867

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://laborke.ru/uplcv?utm_term=manual+de+equivalencia+de+transistores+download PDF link annotation
    • http://xn--54-dlcdkamdj4btild5b.xn--p1ai/ckfinder/userfiles/files/23123870772.pdfIn PDF document text
    • http://duonglaohanoi.com/userfiles/file/lesarogamibewusedewuwun.pdfIn PDF document text
    • https://thietbidienmanhcuong.com/upload/files/zuzuturanele.pdfIn PDF document text
    • https://boumqueur-edition.com/upload/fckeditor/file/76103686399.pdfIn PDF document text
    • http://arc-en-cielproduce.com/ckfinder/userfiles/files/258899107.pdfIn PDF document text
    • http://st-johnson.com/Uploadfiles/files/62284768554.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4e611a3225---42487701183.pdfIn PDF document text
    • https://sygimportaciones.com/wp-content/plugins/super-forms/uploads/php/files/kcv80o0bsop1piuck3ho5tc1fa/zinetuwuvubixuputi.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c23b61a5690---19318766451.pdfIn PDF document text
    • https://www.pennlighting.com/wp-content/plugins/super-forms/uploads/php/files/7ddddd7c837d0cb853c77b8f6c60a9d5/sudopevipeluriboz.pdfIn PDF document text
    • https://lerong.vn/wp-content/plugins/super-forms/uploads/php/files/e5c86b5197204cd3ed3958cb9219a1b3/30550300335.pdfIn PDF document text
    • http://goldenbaycruisesagent.com/userfiles/file/97092845636.pdfIn PDF document text
    • https://bbgpiti.com/userfiles/files/49047336588.pdfIn PDF document text
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607b606971b85---11711027785.pdfIn PDF document text
    • http://insfilings.com/skyzone_classic/upload/files/sonuvesijatakotikudud.pdfIn PDF document text
    • http://gezond-trakteren.nl/kasteel-doornenburg-img/bestandenfile/vovavanumovupek.pdfIn PDF document text
    • http://thuduchouse.vn/pics/file/78177424073.pdfIn PDF document text
    • https://realestateconnect.pro/wp-content/plugins/super-forms/uploads/php/files/m6c87d4httce7doj5varl5jds4/11956082678.pdfIn PDF document text
    • https://jokerprod.net/userfiles/file/90982259046.pdfIn PDF document text
    • https://www.guestquesttravelmedia.com/wp-content/plugins/super-forms/uploads/php/files/2p8auf8a5shpuhhtb1cvr10l4j/sogekunetofuwa.pdfIn PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/2580d2dbfbbf860536d9b02bc54ea827/37516072912.pdfIn PDF document text
    • https://mmagame.com/userfiles/file/404887736.pdfIn PDF document text
    • http://cbelmira.com/wp-content/plugins/super-forms/uploads/php/files/cfgsfs6a3r4iqu5n33c14bea94/zepakijer.pdfIn PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/16073941eacea1---semegiferutal.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/5pj3h5j6n9kmtuc6j8k8k3fn84/61665200792.pdfIn PDF document text
    • http://staging.impactredevelopment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075c2e075b37---44348907043.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16079d2d065ea5---87385178981.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_off000128f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128F1 17888 bytes
SHA-256: 1cc73afef69b84ce980829f0ab0083f70886db41ca8becd7335a1051e9570455
font_01_sfnt_off00015693.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15693 10756 bytes
SHA-256: be5937ba268e09df82d493471104696f4a380b286b353656e0da7cf060c7baaa
font_02_sfnt_off00016f45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16F45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1