Malicious PDF — malware analysis report

Static analysis result for SHA-256 137e1242ca57c95b…

MALICIOUS

PDF

73.1 KB Created: 2021-09-16 22:46:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 857adf4d17f32a7bc3cd6896752303ce SHA-1: aef38ae52a5b9f47d9b41c201ad6416a9688af47 SHA-256: 137e1242ca57c95b4212f92233b07744d9bb4023a260d56f127f12219fb60c57
154 Risk Score

Malware Insights

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

The sample is a PDF document containing embedded JavaScript, which is a common technique for executing malicious code. The presence of numerous external URLs, many of which are part of a link farm, suggests an attempt to distribute malicious content or phish for user credentials. ClamAV detection and ML classification strongly indicate malicious intent, likely involving the exploitation of PDF vulnerabilities to deliver a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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=fluid+mechanics+and+hydraulic+machines+rk+bansal+pdf PDF link annotation
    • http://inistor.com/ufiles/files/befabifagixerijuleziseze.pdfIn PDF document text
    • http://sarkanyhajo.hu/files/file/22572848595.pdfIn PDF document text
    • http://www.hro.ait.ac.th/js/ckfinder/userfiles/files/kujerajajuvaxati.pdfIn PDF document text
    • http://shinies.ru/img/lib/file/lofosubusur.pdfIn PDF document text
    • https://ayurmitra.com/files/file/fesunose.pdfIn PDF document text
    • http://xn--3bsx3iw22bmot.com/filespath/files/20210902055835.pdfIn PDF document text
    • http://www.ags-sib.ru/ckfinder/userfiles/files/jugelidasapikekawutetit.pdfIn PDF document text
    • http://studiotecniconuti.it/userfiles/files/6297336340.pdfIn PDF document text
    • https://www.paparazzirestaurant.com.au/wp-content/plugins/super-forms/uploads/php/files/15f02a2592e3cdcfadba601c54fad582/naxixunumeji.pdfIn PDF document text
    • http://gemwishrs.com/ckfinder/stones/files/5252804993.pdfIn PDF document text
    • http://vipnjl.com/userfiles/files/zavogevixurapikanesutu.pdfIn PDF document text
    • http://bbfederico2.net/userfiles/file/47395748230.pdfIn PDF document text
    • http://meadescafe.com/userfiles/file/daburovejuzarut.pdfIn PDF document text
    • http://xszhuhai.com/uploadfiles/files/netotuvepinumetowupe.pdfIn PDF document text
    • http://www.cddfct.com/up_files/file/zuruxoxufufiputodemevobo.pdfIn PDF document text
    • http://gesundimjob.at/images/content/files/mapamiridifovexuvevade.pdfIn PDF document text
    • https://austdoorcaocap.com/upload/files/taxewinemumumorilafufo.pdfIn PDF document text
    • http://cistenivytahu.cz/upload/file/57401895922.pdfIn PDF document text
    • http://abworder.com/uploads/files/logodovuvirivojuduva.pdfIn PDF document text
    • http://dobre-jaja.com/Upload/file/32460890504.pdfIn PDF document text
    • http://avandcie-automation.fr/ckfinder/userfiles/files/57359684222.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_off0000b93f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB93F 11092 bytes
SHA-256: 7d695037e60f9c4a2689b8105957e664543c0fc01aee1fbafdbc153ec998837c
font_01_sfnt_off0000d29f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD29F 17284 bytes
SHA-256: 47d99634681ccdf031760668b191a97bad47e083dd86e3591bb59b67ecce9a4a
font_02_sfnt_off0000fef7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1