Malicious PDF — malware analysis report

Static analysis result for SHA-256 a50f665a028cbcfe…

MALICIOUS

PDF

136.1 KB Created: 2020-10-08 09:47:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 75c3208fe7a9a81c6aa419c113656f7d SHA-1: a3fbef62b6e590e3666fb893d404635eaca50ad7 SHA-256: a50f665a028cbcfedb03dd2ba4f003432db3e8cf6fc445050d7a796115a00058
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a large number of embedded links, many pointing to disposable domains, characteristic of a link farm. One of these links, 'https://cctraff.ru/strik?keyword=sumerian+cuneiform+alphabet+translation', is identified as malicious redirector infrastructure. The ML classifier also strongly flagged this PDF as malicious, supporting the assessment of a malicious link distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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.
  • 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://cctraff.ru/strik?keyword=sumerian+cuneiform+alphabet+translation In PDF document text
    • http://files.klmny.com/uploads/1/3/1/4/131454459/1483729.pdfIn PDF document text
    • http://files.noragibsoncontemporaryballet.com/uploads/1/3/1/0/131071188/2173710.pdfIn PDF document text
    • http://files.jtrading.dk/uploads/1/3/1/4/131483002/3558267.pdfIn PDF document text
    • http://files.foodwebfarms.com/uploads/1/3/1/8/131857284/880356.pdfIn PDF document text
    • http://files.revolutioninkstudio.com/uploads/1/3/1/3/131378943/8599303.pdfIn PDF document text
    • https://site-1038494.mozfiles.com/files/1038494/zepurakezogeferepule.pdfIn PDF document text
    • https://site-1036811.mozfiles.com/files/1036811/8593818979.pdfIn PDF document text
    • https://site-1044184.mozfiles.com/files/1044184/22952928316.pdfIn PDF document text
    • https://site-1039188.mozfiles.com/files/1039188/torejirefobeto.pdfIn PDF document text
    • https://site-1038530.mozfiles.com/files/1038530/vedidajosisuvefode.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/e8c043c0-59ee-4d77-a47d-2fc2af60ef06/51487224744.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cccaa92b-85a1-4652-82c1-d8bf96f149f5/merajesiriremazusezixilo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/605136ff-6ead-473c-8950-cead7bb6ebf5/foxufetuk.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ed3957d7-bde5-4007-864d-659c97c4f717/74542437270.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://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text
    • https://savannah.gnu.org/projects/freefont/In PDF document text
    • http://www.gnu.org/licenses/In PDF document text
    • http://www.gnu.org/copyleft/gpl.htmlIn PDF document text

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001897d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1897D 5716 bytes
SHA-256: c6c3ee58a16fed12d6766410b9e2e50e8940d01e1f1b609951c7e8095694e1eb
font_01_sfnt_off00019d2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19D2A 5500 bytes
SHA-256: fd49523ed6db721f75d68372a1f51b4ed98ada3f5cf99384eeb08d8f7774015c
font_02_sfnt_off0001afa8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1AFA8 18636 bytes
SHA-256: 348a5d96e44155eaac6ef9f00ac153ee75206a61356275bd2b0471aa6d43d09d
font_03_sfnt_off0001e5e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1E5E8 16316 bytes
SHA-256: aca9d55988c6676475e3b08f81553e0332b16fe059812fe008bdba06dc22cfc1
font_04_sfnt_off0001fb77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1FB77 8428 bytes
SHA-256: ef1b495081f24bbda60031411cdc400b520c4bccf25683ec23cb1c613a6b057c